Introducing wave energy into the renewable energy marketplace

International Nuclear Information System (INIS)

Petroncini, S.; Yemm, R.W.

2001-01-01

The energy sector in Europe is going through a dynamic evolution that sees the introduction and development of renewable energy and the re-emergence of a wave energy industry. Although wave energy is currently not economically competitive with mature technologies such as wind energy, the wave energy world-wide resource of 2 TW has a potential contribution in the electricity market of 2000TWh/year. Denmark, Ireland, Portugal, Norway and the UK have been analysed in terms of wave energy resources, renewable energy market structure and political and economic support for the introduction of wave energy into the marketplace. The results have been used together with Ocean Power Delivery Ltd to develop an initial market survey for the wave energy converter Pelamis. (au)

Impacts of wave energy conversion devices on local wave climate: observations and modelling from the Perth Wave Energy Project

Science.gov (United States)

Hoeke, Ron; Hemer, Mark; Contardo, Stephanie; Symonds, Graham; Mcinnes, Kathy

2016-04-01

As demonstrated by the Australian Wave Energy Atlas (AWavEA), the southern and western margins of the country possess considerable wave energy resources. The Australia Government has made notable investments in pre-commercial wave energy developments in these areas, however little is known about how this technology may impact local wave climate and subsequently affect neighbouring coastal environments, e.g. altering sediment transport, causing shoreline erosion or accretion. In this study, a network of in-situ wave measurement devices have been deployed surrounding the 3 wave energy converters of the Carnegie Wave Energy Limited's Perth Wave Energy Project. This data is being used to develop, calibrate and validate numerical simulations of the project site. Early stage results will be presented and potential simulation strategies for scaling-up the findings to larger arrays of wave energy converters will be discussed. The intended project outcomes are to establish zones of impact defined in terms of changes in local wave energy spectra and to initiate best practice guidelines for the establishment of wave energy conversion sites.

Wave Dragon Wave Energy Converters Used as Coastal Protection

DEFF Research Database (Denmark)

Nørgaard, Jørgen Harck; Andersen, Thomas Lykke; Kofoed, Jens Peter

2011-01-01

This paper deals with wave energy converters used to reduce the wave height along shorelines. For this study the Wave Dragon wave energy converter is chosen. The wave height reduction from a single device has been evaluated from physical model tests in scale 1:51.8 of the 260 x 150 m, 24 kW/m model...... Spain, to evaluate the potential for reducing wave heights close the shore by means of Wave Dragons....

Experimental Measurement of Wave Field Variations around Wave Energy Converter Arrays

Directory of Open Access Journals (Sweden)

Louise O’Boyle

2017-01-01

Full Text Available Wave energy converters (WECs inherently extract energy from incident waves. For wave energy to become a significant power provider in the future, large farms of WECs will be required. This scale of energy extraction will increase the potential for changes in the local wave field and coastal environment. Assessment of these effects is necessary to inform decisions on the layout of wave farms for optimum power output and minimum environmental impact, as well as on potential site selection. An experimental campaign to map, at high resolution, the wave field variation around arrays of 5 oscillating water column WECs and a methodology for extracting scattered and radiated waves is presented. The results highlight the importance of accounting for the full extent of the WEC behavior when assessing impacts on the wave field. The effect of radiated waves on the wave field is not immediately apparent when considering changes to the entire wave spectrum, nor when observing changes in wave climate due to scattered and radiated waves superimposed together. The results show that radiated waves may account for up to 50% of the effects on wave climate in the near field in particular operating conditions.

Wave Energy Potential in the Eastern Mediterranean Levantine Basin. An Integrated 10-year Study

Science.gov (United States)

2014-01-01

SUBTITLE Wave energy potential in the Eastern Mediterranean Levantine Basin. An integrated 10-year study 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c... Cardone CV, Ewing JA, et al. The WAM model e a third generation ocean wave prediction model. J Phys Oceanogr 1988;18(12):1775e810. [70] Varinou M

Wave power potential in Malaysian territorial waters

Science.gov (United States)

Asmida Mohd Nasir, Nor; Maulud, Khairul Nizam Abdul

2016-06-01

Up until today, Malaysia has used renewable energy technology such as biomass, solar and hydro energy for power generation and co-generation in palm oil industries and also for the generation of electricity, yet, we are still far behind other countries which have started to optimize waves for similar production. Wave power is a renewable energy (RE) transported by ocean waves. It is very eco-friendly and is easily reachable. This paper presents an assessment of wave power potential in Malaysian territorial waters including waters of Sabah and Sarawak. In this research, data from Malaysia Meteorology Department (MetMalaysia) is used and is supported by a satellite imaginary obtained from National Aeronautics and Space Administration (NASA) and Malaysia Remote Sensing Agency (ARSM) within the time range of the year 1992 until 2007. There were two types of analyses conducted which were mask analysis and comparative analysis. Mask analysis of a research area is the analysis conducted to filter restricted and sensitive areas. Meanwhile, comparative analysis is an analysis conducted to determine the most potential area for wave power generation. Four comparative analyses which have been carried out were wave power analysis, comparative analysis of wave energy power with the sea topography, hot-spot area analysis and comparative analysis of wave energy with the wind speed. These four analyses underwent clipping processes using Geographic Information System (GIS) to obtain the final result. At the end of this research, the most suitable area to develop a wave energy converter was found, which is in the waters of Terengganu and Sarawak. Besides that, it was concluded that the average potential energy that can be generated in Malaysian territorial waters is between 2.8kW/m to 8.6kW/m.

Coherent Wave Measurement Buoy Arrays to Support Wave Energy Extraction

Science.gov (United States)

Spada, F.; Chang, G.; Jones, C.; Janssen, T. T.; Barney, P.; Roberts, J.

2016-02-01

Wave energy is the most abundant form of hydrokinetic energy in the United States and wave energy converters (WECs) are being developed to extract the maximum possible power from the prevailing wave climate. However, maximum wave energy capture is currently limited by the narrow banded frequency response of WECs as well as extended protective shutdown requirements during periods of large waves. These limitations must be overcome in order to maximize energy extraction, thus significantly decreasing the cost of wave energy and making it a viable energy source. Techno-economic studies of several WEC devices have shown significant potential to improve wave energy capture efficiency through operational control strategies that incorporate real-time information about local surface wave motions. Integral Consulting Inc., with ARPA-E support, is partnering with Sandia National Laboratories and Spoondrift LLC to develop a coherent array of wave-measuring devices to relay and enable the prediction of wave-resolved surface dynamics at a WEC location ahead of real time. This capability will provide necessary information to optimize power production of WECs through control strategies, thereby allowing for a single WEC design to perform more effectively across a wide range of wave environments. The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000514.

The Potential for Wave Energy in the North Sea

DEFF Research Database (Denmark)

Sørensen, H. C.; Chozas, Julia Fernandez

2010-01-01

The North Sea has not yet been regarded as prime area for wave energy development in Europe except in Denmark, Benelux and Germany. The reason is the relatively low intensity of waves (12-17kW/m) compared to the Atlantic with a wave climate of 24-48kW/m. Further on the design wave load is almost ...... is resulting in a prediction of a yearly production of 23TWh; the latter is estimating a yearly production of 77TWh. This equals to 6% of the electricity demand around the North Sea, where the annual electricity consumption is about 1,300TWh.......The North Sea has not yet been regarded as prime area for wave energy development in Europe except in Denmark, Benelux and Germany. The reason is the relatively low intensity of waves (12-17kW/m) compared to the Atlantic with a wave climate of 24-48kW/m. Further on the design wave load is almost...... as in the Atlantic and the distance to shore relatively long compared to sites with good wave climate like Ireland, Portugal, Spain and the west coast of UK. The increasing activities within offshore wind in the North Sea and the attempt to build a super grid connecting the wind sites with the major consumers around...

SSG Wave Energy Converter

DEFF Research Database (Denmark)

Margheritini, Lucia; Vicinanza, Diego; Frigaard, Peter

2008-01-01

The SSG (Sea Slot-cone Generator) is a wave energy converter of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level, in which the water of incoming waves is stored temporary. In each reservoir, expressively designed low...... head hydroturbines are converting the potential energy of the stored water into power. A key to success for the SSG will be the low cost of the structure and its robustness. The construction of the pilot plant is scheduled and this paper aims to describe the concept of the SSG wave energy converter...

The potential of wave and offshore wind energy in around the coastline of Malaysia that face the South China Sea

International Nuclear Information System (INIS)

Chiang, E.P.; Zainal, Z.A.; Aswatha Narayana, P.A.; Seetharamu, K.N.

2006-01-01

The world wide estimated wave resource is more than 2 TW. Offshore wind speeds are generally higher than wind speeds over land, hence higher available energy resource. The estimated offshore wind potential in European waters alone is in excess of 2500 TWh/annum. Offshore area also provides larger area for deploying wind energy devices. In recent year efforts to promote these two types of renewable and green energy sources have been intensify. Using the data obtained from the Malaysia Meteorological Service (MMS) analysis was conducted for the potential of wave energy and wind energy along the coastline of Malaysia facing the South China Sea. Maps of wave power potential were produced. The mean vector wind speed and direction were tabulated

Wave energy potential: A forecasting system for the Mediterranean basin

International Nuclear Information System (INIS)

Carillo, Adriana; Sannino, Gianmaria; Lombardi, Emanuele

2015-01-01

ENEA is performing ocean wave modeling activities with the aim of both characterizing the Italian sea energy resource and providing the information necessary for the experimental at sea and operational phases of energy converters. Therefore a forecast system of sea waves and of the associated energy available has been developed and has been operatively running since June 2013. The forecasts are performed over the entire Mediterranean basin and, at a higher resolution, over ten sub-basins around the Italian coasts. The forecast system is here described along with the validation of the wave heights, performed by comparing them with the measurements from satellite sensors. [it

A high-resolution assessment of wind and wave energy potentials in the Red Sea

KAUST Repository

Langodan, Sabique; Viswanadhapalli, Yesubabu; Dasari, Hari Prasad; Knio, Omar; Hoteit, Ibrahim

2016-01-01

This study presents an assessment of the potential for harvesting wind and wave energy from the Red Sea based on an 18-year high-resolution regional atmospheric reanalysis recently generated using the Advanced Weather Research Forecasting model

Energy in one-dimensional linear waves

International Nuclear Information System (INIS)

Repetto, C E; Roatta, A; Welti, R J

2011-01-01

This work is based on propagation phenomena that conform to the classical wave equation. General expressions of power, the energy conservation equation in continuous media and densities of the kinetic and potential energies are presented. As an example, we study the waves in a string and focused attention on the case of standing waves. The treatment is applicable to introductory science textbooks. (letters and comment)

Cycloidal Wave Energy Converter

Energy Technology Data Exchange (ETDEWEB)

Stefan G. Siegel, Ph.D.

2012-11-30

exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.

Wave Resource Characterization at US Wave Energy Converter (WEC) Test Sites

Science.gov (United States)

Dallman, A.; Neary, V. S.

2016-02-01

The US Department of Energy's (DOE) Marine and Hydrokinetic energy (MHK) Program is supporting a diverse research and development portfolio intended to accelerate commercialization of the marine renewable industry by improving technology performance, reducing market barriers, and lowering the cost of energy. Wave resource characterization at potential and existing wave energy converter (WEC) test sites and deployment locations contributes to this DOE goal by providing a catalogue of wave energy resource characteristics, met-ocean data, and site infrastructure information, developed utilizing a consistent methodology. The purpose of the catalogue is to enable the comparison of resource characteristics among sites to facilitate the selection of test sites that are most suitable for a developer's device and that best meet their testing needs and objectives. It also provides inputs for the design of WEC test devices and planning WEC tests, including the planning of deployment and operations and maintenance. The first edition included three sites: the Pacific Marine Energy Center (PMEC) North Energy Test Site (NETS) offshore of Newport, Oregon, the Kaneohe Bay Naval Wave Energy Test Site (WETS) offshore of Oahu, HI, and a potential site offshore of Humboldt Bay, CA (Eureka, CA). The second edition was recently finished, which includes five additional sites: the Jennette's Pier Wave Energy Converter Test Site in North Carolina, the US Army Corps of Engineers (USACE) Field Research Facility (FRF), the PMEC Lake Washington site, the proposed PMEC South Energy Test Site (SETS), and the proposed CalWave Central Coast WEC Test Site. The operational sea states are included according to the IEC Technical Specification on wave energy resource assessment and characterization, with additional information on extreme sea states, weather windows, and representative spectra. The methodology and a summary of results will be discussed.

A Relation Between the Eikonal Equation Associated to a Potential Energy Surface and a Hyperbolic Wave Equation.

Science.gov (United States)

Bofill, Josep Maria; Quapp, Wolfgang; Caballero, Marc

2012-12-11

The potential energy surface (PES) of a molecule can be decomposed into equipotential hypersurfaces. We show in this article that the hypersurfaces are the wave fronts of a certain hyperbolic partial differential equation, a wave equation. It is connected with the gradient lines, or the steepest descent, or the steepest ascent lines of the PES. The energy seen as a reaction coordinate plays the central role in this treatment.

Power from the seas - Wave energy has a big future

International Nuclear Information System (INIS)

Schenler, W.

2008-01-01

This article takes a look at how the energy of the oceans' waves can become an important source of energy. The generation of the energy contained in waves as an indirect form of solar energy is described. The energy potential offered is quoted as being high in the Atlantic near England and Scotland. The article goes on the discuss the technical potential of this form of renewable energy and provides a map showing this. Financial aspects and economic potentials are discussed. Effects on the environment are also discussed. The on-shore and off-shore technologies that can be used to capture wave energy are described and discussed, as is the combination of power production from wind and waves

Waves energy comes to surface

International Nuclear Information System (INIS)

Guezel, J.Ch.

2006-01-01

The wave- or thalasso-energy, potentially as promising as wind energy, have started to develop in Europe. Great Britain has already a good experience in this domain but France shows also ambitions in this beginning industry with several projects in progress. This article makes an overview of the existing tide-, current- and wave-powered generators: tide mills, underwater hydro-turbines, immersed linear generators, air-compression systems, buoy systems, etc. (J.S.)

Marine Waves Energy: A spatio-temporal DSS-WebGIS to support the wave-energy potential assessment in the Mediterranean Sea

International Nuclear Information System (INIS)

Pollino, Maurizio; La Porta, Luigi; Caiaffa, Emanuela

2015-01-01

GIS technologies are able to provide a useful tool for estimating the energy resource from the sea waves, assessing whether this energy flux is exploitable and evaluating the social and environmental impacts in deep water and/or in the seaboard. The DDS-WebGIS 'Energy Waves' represents a tool for displaying and sharing geo spatial data and maps, as well as a valuable support for new installations planning, forecasting system and existing infrastructure management. [it

Energy Capture Optimization for an Adaptive Wave Energy Converter

NARCIS (Netherlands)

Barradas Berglind, Jose de Jesus; Meijer, Harmen; van Rooij, Marijn; Clemente Pinol, Silvia; Galvan Garcia, Bruno; Prins, Wouter; Vakis, Antonis I.; Jayawardhana, Bayu

2016-01-01

Wave energy has great potential as a renewable energy source, and can therefore contribute significantly to the proportion of renewable energy in the global energy mix. This is especially important since energy mixes with high renewable penetration have become a worldwide priority. One solution to

Electromagnetic Lead Screw for Potential Wave Energy Application

DEFF Research Database (Denmark)

Lu, Kaiyuan; Wu, Weimin

2014-01-01

This paper presents a new type electromagnetic lead screw (EMLS) intended for wave energy application. Similar to the mechanical lead screw, this electromagnetic version can transfer slow linear motion to high-rotational motion, offering gearing effects. Compared with the existing pure magnetic...

The Potential Energy Density in Transverse String Waves Depends Critically on Longitudinal Motion

Science.gov (United States)

Rowland, David R.

2011-01-01

The question of the correct formula for the potential energy density in transverse waves on a taut string continues to attract attention (e.g. Burko 2010 "Eur. J. Phys." 31 L71), and at least three different formulae can be found in the literature, with the classic text by Morse and Feshbach ("Methods of Theoretical Physics" pp 126-127) stating…

On the wave energy potential along the southern coast of Brazil

Energy Technology Data Exchange (ETDEWEB)

Assis, Leandro Eduardo; Beluco, Alexandre; de Almeida, Luiz Emilio B. [Inst. Pesquisas Hidraulicas, Univ. Fed Rio Grande do Sul, Porto Alegre (Brazil)

2013-07-01

The ocean wave energy resource is a real alternative to supply part of the energy demand in various countries, since some locations have a remarkable capacity to generate electricity. The objective of this study is to evaluate the energy resource of ocean waves in the coast of Rio Grande do Sul, the southern state of Brazil. This note presents the first results. The wave data used were collected in the sea area near the Port of Rio Grande during the years 1996 to 1999, amounting to sixteen months of monitoring. The data set was treated and grouped resulting information monthly, seasonal and annual basis. The annual average was found to be 8.6 kW per meter of wave front, reaching 14.0 kW per meter for the month of May and 4.0 kW per meter for the month of January. The results indicate good perspectives in obtaining power supplies.

Gravitational Waves from Oscillons with Cuspy Potentials.

Science.gov (United States)

Liu, Jing; Guo, Zong-Kuan; Cai, Rong-Gen; Shiu, Gary

2018-01-19

We study the production of gravitational waves during oscillations of the inflaton around the minimum of a cuspy potential after inflation. We find that a cusp in the potential can trigger copious oscillon formation, which sources a characteristic energy spectrum of gravitational waves with double peaks. The discovery of such a double-peak spectrum could test the underlying inflationary physics.

Probabilistic Design of Wave Energy Devices

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard; Kofoed, Jens Peter; Ferreira, C.B.

2011-01-01

Wave energy has a large potential for contributing significantly to production of renewable energy. However, the wave energy sector is still not able to deliver cost competitive and reliable solutions. But the sector has already demonstrated several proofs of concepts. The design of wave energy...... devices is a new and expanding technical area where there is no tradition for probabilistic design—in fact very little full scale devices has been build to date, so it can be said that no design tradition really exists in this area. For this reason it is considered to be of great importance to develop...... and advocate for a probabilistic design approach, as it is assumed (in other areas this has been demonstrated) that this leads to more economical designs compared to designs based on deterministic methods. In the present paper a general framework for probabilistic design and reliability analysis of wave energy...

Proposed electromagnetic wave energy converter

Science.gov (United States)

Bailey, R. L.

1973-01-01

Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

Assessing the Wave Energy Potential of Jamaica, a Greater Antilles Island, through Dynamic Modelling

Science.gov (United States)

Daley, A. P., Jr.; Dorville, J. F. M.; Taylor, M. A.

2017-12-01

Globally wave energy has been on the rise as a result of the impacts of climate change and continuous fluctuation in oil prices. The water's inertia provides waves with greater stability than that of other renewable energy sources such as solar and wind. Jamaica is part of the Greater Antilles Arc and has over 1000 km of coast line with an abundance of shallow water approximately 80% within a 50km band. This configuration provides a wealth of sites for wave exploitation even in minimal wave energy conditions. Aside from harnessing the oceans waves converters can be viewed as a tool for protection of coastal areas against natural marine occurrences. Jamica has done extensive studies where solar, hydro and wind resouces are concerned. However, there has been no studies done to date on the country's wave energy resources.The aim of this study is to bridge this gap by characterizing Jamaica's wave energy resources generating in a half-closed Caribbean Sea using data available from: buoys, altimetric satellite, and numerical model. Available data has been used to assess the available resource on the coastal area for the last 12 years. Statistical analysis of the available energy is determined using the sea state (Hs, Tp and Dir) and the atmospheric forcing (10m-wind, atmospheric pressure, sea-air temperature) relating to the season.The chain of dynamical model is presented (WW3-SWAN-SWASH), allowing for the tracking of the propagation of the wave energy from an offshore region to nearshore zone along with their interaction with areas of shallow depth. This will provide a better assessment of the energy and the quality of the waves closer to the electrical grid.Climate prediction is used to estimate the sea state and wave energy exploitable up to 2100. An analysis of the possible usage of the available coastal resource up to 2100. The main results present small but exploitable resources with seasonal variability in the energy available but not wave direction.

Are Wave and Tidal Energy Plants New Green Technologies?

Science.gov (United States)

Douziech, Mélanie; Hellweg, Stefanie; Verones, Francesca

2016-07-19

Wave and tidal energy plants are upcoming, potentially green technologies. This study aims at quantifying their various potential environmental impacts. Three tidal stream devices, one tidal range plant and one wave energy harnessing device are analyzed over their entire life cycles, using the ReCiPe 2008 methodology at midpoint level. The impacts of the tidal range plant were on average 1.6 times higher than the ones of hydro-power plants (without considering natural land transformation). A similar ratio was found when comparing the results of the three tidal stream devices to offshore wind power plants (without considering water depletion). The wave energy harnessing device had on average 3.5 times higher impacts than offshore wind power. On the contrary, the considered plants have on average 8 (wave energy) to 20 (tidal stream), or even 115 times (tidal range) lower impact than electricity generated from coal power. Further, testing the sensitivity of the results highlighted the advantage of long lifetimes and small material requirements. Overall, this study supports the potential of wave and tidal energy plants as alternative green technologies. However, potential unknown effects, such as the impact of turbulence or noise on marine ecosystems, should be further explored in future research.

Efficient Wave Energy Amplification with Wave Reflectors

DEFF Research Database (Denmark)

Kramer, Morten Mejlhede; Frigaard, Peter Bak

2002-01-01

Wave Energy Converters (WEC's) extract wave energy from a limited area, often a single point or line even though the wave energy is generally spread out along the wave crest. By the use of wave reflectors (reflecting walls) the wave energy is effectively focused and increased to approximately 130......-140%. In the paper a procedure for calculating the efficiency and optimizing the geometry of wave reflectors are described, this by use of a 3D boundary element method. The calculations are verified by laboratory experiments and a very good agreement is found. The paper gives estimates of possible power benifit...... for different geometries of the wave reflectors and optimal geometrical design parameters are specified. On this basis inventors of WEC's can evaluate whether a specific WEC possible could benefit from wave reflectors....

Exploring the Potential for Increased Production from the Wave Energy Converter Lifesaver by Reactive Control

Directory of Open Access Journals (Sweden)

Marta Molinas

2013-07-01

Full Text Available Fred Olsen is currently testing their latest wave energy converter (WEC, Lifesaver, outside of Falmouth Bay in England, preparing it for commercial operation at the Wavehub test site. Previous studies, mostly focusing on hydrodynamics and peak to average power reduction, have shown that this device has potential for increased power extraction using reactive control. This article extends those analyses, adding a detailed model of the all-electric power take-off (PTO system, consisting of a permanent magnet synchronous generator, inverter and DC-link. Time domain simulations are performed to evaluate the PTO capabilities of the modeled WEC. However, when tuned towards reactive control, the generator losses become large, giving a very low overall system efficiency. Optimal control with respect to electrical output power is found to occur with low added mass, and when compared to pure passive loading, a 1% increase in annual energy production is estimated. The main factor reducing the effect of reactive control is found to be the minimum load-force constraint of the device. These results suggest that the Lifesaver has limited potential for increased production by reactive control. This analysis is nevertheless valuable, as it demonstrates how a wave-to-wire model can be used for investigation of PTO potential, annual energy production estimations and evaluations of different control techniques for a given WEC device.

Modeling the Buoyancy System of a Wave Energy Power Plant

DEFF Research Database (Denmark)

Pedersen, Tom S.; Nielsen, Kirsten M.

2009-01-01

A nonlinear dynamic model of the buoyancy system in a wave energy power plant is presented. The plant ("Wave Dragon") is a floating device using the potential energy in overtopping waves to produce power. A water reservoir is placed on top of the WD, and hydro turbines lead the water to the sea...... producing electrical power. Through air chambers it is possible to control the level of the WD. It is important to control the level in order to maximize the power production in proportion to the wave height, here the amount of overtopping water and the amount of potential energy is conflicting...

The influence of waves on the tidal kinetic energy resource at a tidal stream energy site

International Nuclear Information System (INIS)

Guillou, Nicolas; Chapalain, Georges; Neill, Simon P.

2016-01-01

Highlights: • We model the influence of waves on tidal kinetic energy in the Fromveur Strait. • Numerical results are compared with field data of waves and currents. • The introduction of waves improve predictions of tidal stream power during storm. • Mean spring tidal stream potential is reduced by 12% during extreme wave conditions. • Potential is reduced by 7.8% with waves forces and 5.3% with enhanced friction. - Abstract: Successful deployment of tidal energy converters relies on access to accurate and high resolution numerical assessments of available tidal stream power. However, since suitable tidal stream sites are located in relatively shallow waters of the continental shelf where tidal currents are enhanced, tidal energy converters may experience effects of wind-generated surface-gravity waves. Waves may thus influence tidal currents, and associated kinetic energy, through two non-linear processes: the interaction of wave and current bottom boundary layers, and the generation of wave-induced currents. Here, we develop a three-dimensional tidal circulation model coupled with a phase-averaged wave model to quantify the impact of the waves on the tidal kinetic energy resource of the Fromveur Strait (western Brittany) - a region that has been identified with strong potential for tidal array development. Numerical results are compared with in situ observations of wave parameters (significant wave height, peak period and mean wave direction) and current amplitude and direction 10 m above the seabed (the assumed technology hub height for this region). The introduction of waves is found to improve predictions of tidal stream power at 10 m above the seabed at the measurement site in the Strait, reducing kinetic energy by up to 9% during storm conditions. Synoptic effects of wave radiation stresses and enhanced bottom friction are more specifically identified at the scale of the Strait. Waves contribute to a slight increase in the spatial gradient of

Statistical investigation of expected wave energy and its reliability

International Nuclear Information System (INIS)

Ozger, M.; Altunkaynak, A.; Sen, Z.

2004-01-01

The statistical behavior of wave energy at a single site is derived by considering simultaneous variations in the period and wave height. In this paper, the general wave power formulation is derived by using the theory of perturbation. This method leads to a general formulation of the wave power expectation and other statistical parameter expressions, such as standard deviation and coefficient of variation. The statistical parameters, namely the mean value and variance of wave energy, are found in terms of the simple statistical parameters of period, significant wave height and zero up-crossing period. The elegance of these parameters is that they are distribution free. These parameters provide a means for defining the wave energy distribution function by employing the Chebyschev's inequality. Subsequently, an approximate probability distribution function of the wave energy is also derived for assessment of risk and reliability associated with wave energy. Necessary simple charts are given for risk and reliability assessments. Two procedures are presented for such assessments in wave energy calculations and the applications of these procedures are provided for wave energy potential assessment in the regions of the Pacific Ocean off the west coast of U.S. (author)

Statistical investigation of expected wave energy and its reliability

International Nuclear Information System (INIS)

Oezger, Mehmet; Altunkaynak, Abduesselam; Sen, Zekai

2004-01-01

The statistical behavior of wave energy at a single site is derived by considering simultaneous variations in the period and wave height. In this paper, the general wave power formulation is derived by using the theory of perturbation. This method leads to a general formulation of the wave power expectation and other statistical parameter expressions, such as standard deviation and coefficient of variation. The statistical parameters, namely the mean value and variance of wave energy, are found in terms of the simple statistical parameters of period, significant wave height and zero up-crossing period. The elegance of these parameters is that they are distribution free. These parameters provide a means for defining the wave energy distribution function by employing the Chebyschev's inequality. Subsequently, an approximate probability distribution function of the wave energy is also derived for assessment of risk and reliability associated with wave energy. Necessary simple charts are given for risk and reliability assessments. Two procedures are presented for such assessments in wave energy calculations and the applications of these procedures are provided for wave energy potential assessment in the regions of the Pacific Ocean off the west coast of U.S

Wave energy and its possibilities in the Danish power supplies

International Nuclear Information System (INIS)

Traeholt Madsen, N.; Lorenzen, S.; Haunstrup Christensen, T.

1997-06-01

Mathematical theory of wave forces (wave height, spectrua, energy distribution and effect) is summarized. An attempt to estimate the Danish wave power potential on the basis of previous investigations og wave effect in various regions is presented. A brief review of wave energy applications and research constitutes basis for two scenarios of wave power adjustment into the 'Green society'. Power quality, environment, economics and supply reliability are estimated. (EG) 42 refs

Assessment of wave energy resources in Hawaii

International Nuclear Information System (INIS)

Stopa, Justin E.; Cheung, Kwok Fai; Chen, Yi-Leng

2011-01-01

Hawaii is subject to direct approach of swells from distant storms as well as seas generated by trade winds passing through the islands. The archipelago creates a localized weather system that modifies the wave energy resources from the far field. We implement a nested computational grid along the major Hawaiian Islands in the global WaveWatch3 (WW3) model and utilize the Weather Research and Forecast (WRF) model to provide high-resolution mesoscale wind forcing over the Hawaii region. Two hindcast case studies representative of the year-round conditions provide a quantitative assessment of the regional wind and wave patterns as well as the wave energy resources along the Hawaiian Island chain. These events of approximately two weeks each have a range of wind speeds, ground swells, and wind waves for validation of the model system with satellite and buoy measurements. The results demonstrate the wave energy potential in Hawaii waters. While the episodic swell events have enormous power reaching 60 kW/m, the wind waves, augmented by the local weather, provide a consistent energy resource of 15-25 kW/m throughout the year. (author)

Wave Energy Resource along the Coast of Santa Catarina (Brazil

Directory of Open Access Journals (Sweden)

Pasquale Contestabile

2015-12-01

Full Text Available Brazil has one of the largest electricity markets in South America, which needs to add 6000 MW of capacity every year in order to satisfy growing the demand from an increasing and more prosperous population. Apart from biomass, no other renewable energy sources, besides hydroelectricity, play a relevant role in the energy mix. The potential for wind and wave energy is very large. Brazil's Santa Catarina state government is starting a clean energy program in the state, which is expected to bring more than 1 GW of capacity. Assessment of wave energy resources is needed along the coastline. This work studied the potential wave energy along the north-central coasts of Santa Catarina, in Southern Brazil, by analysis of the hindcast data from the European Centre for Medium-Range Weather Forecasts (ECMWF. The annual offshore wave power was found to be equal to 15.25 kW/m, the bulk of which is provided by southeastern waves. The nearshore energetic patterns were studied by means of a numerical coastal propagation model (Mike21 SW. The mean wave power of 20 m isobaths is 11.43 kW/m. Supplementary considerations are drawn on realistic perspectives for wave energy converters installations.

Parametric pendulum based wave energy converter

Science.gov (United States)

Yurchenko, Daniil; Alevras, Panagiotis

2018-01-01

The paper investigates the dynamics of a novel wave energy converter based on the parametrically excited pendulum. The herein developed concept of the parametric pendulum allows reducing the influence of the gravity force thereby significantly improving the device performance at a regular sea state, which could not be achieved in the earlier proposed original point-absorber design. The suggested design of a wave energy converter achieves a dominant rotational motion without any additional mechanisms, like a gearbox, or any active control involvement. Presented numerical results of deterministic and stochastic modeling clearly reflect the advantage of the proposed design. A set of experimental results confirms the numerical findings and validates the new design of a parametric pendulum based wave energy converter. Power harvesting potential of the novel device is also presented.

Adiabatic energy change of plasma electrons and the frame dependence of the cross-shock potential at collisionless magnetosonic shock waves

International Nuclear Information System (INIS)

Goodrich, C.C.; Scudder, J.D.

1984-01-01

In collisionless magnetosonic shock waves, ions are commonly thought to be decelerated by dc electrostatic cross-shock electric field along the shock normal n. In a frame where ions are normally incident to the shock the change in the potential energy [qphi/sup N/] in the quasi-perpendicular geommetry is of the order of the change of the energy of normal ion flow: [qphi/sup N/]roughly-equal[1/2m/sub i/(V/sub i//sup N/xn) 2 ], which is approximately 200-500 eV at the earth's bow shock. We show that the electron energy gain, typically 1/10 this number, is consistent with such a large potential jump in this geometry. Key facts are the different paths taken by electrons an ions through the shock wave and the frame dependence of the potential jump in the geometry. In the normal incidence frame, electrons lose energy by doing work against the solar wind motional electric field E/sub M//sup N/, which partially offsets the energy gain from the cross-shock electrostatic potential energy [ephi/sub asterisk//sup N/]. In the de Hoffman-Teller frame the motional electric field vanishes; the elctrons gain the full electrostatic potential energy jump e[phi/sub asterisk//sup H//sup T/] of that frame, which is not, however, equal to the electrostatic potential energy jump e[phi/sub asterisk//sup N/] of that frame, which is not, however, equal to the electrostatic potential energy jump e[phi/sub asterisk//sup N/] in the normal incidence frame

Energy Properties of Ion Acoustic Waves in Stable and Unstable Plasmas

DEFF Research Database (Denmark)

Jensen, Vagn Orla; Lynov, Jens-Peter

1979-01-01

Energy exchange between potential energy and ion kinetic energy in an ion acoustic wave is considered. In order to investigate the linear Landau damping or growth, the energy is calculated by use of first‐order quantities only so that nonlinear effects are not involved. It is found that for ion...... acoustic waves that are growing or damped in space the time average of the sum of the potential and the kinetic energy density is independent of position. Energy absorption spectra in particle velocity space are calculated; they are relatively broad and complicated functions. This shows that plasma ions...... of all velocities exchange energy with the wave....

Reflectors to Focus Wave Energy

DEFF Research Database (Denmark)

Kramer, Morten; Frigaard, Peter

2005-01-01

Wave Energy Converters (WEC’s) extract wave energy from a limited area, often a single point or line even though the wave energy is generally spread out along the wave crest. By the use of wave reflectors (reflecting walls) the wave energy is effectively focused and increased by approximately 30......-50%. Clearly longer wave reflectors will focus more wave energy than shorter wave reflectors. Thus the draw back is the increased wave forces for the longer wave reflectors. In the paper a procedure for calculating the energy efficiency and the wave forces on the reflectors are described, this by use of a 3D...... boundary element method. The calculations are verified by laboratory experiments and a very good agreement is found. The paper gives estimates of possible power benefit for different wave reflector geometries and optimal geometrical design parameters are specified. On this basis inventors of WEC’s can...

Transfer of a wave packet in double-well potential

Science.gov (United States)

Yang, Hai-Feng; Hu, Yao-Hua; Tan, Yong-Gang

2018-04-01

Energy potentials with double-well structures are typical in atoms and molecules systems. A manipulation scheme using Half Cycles Pulses (HCPs) is proposed to transfer a Gaussian wave packet between the two wells. On the basis of quantum mechanical simulations, the time evolution and the energy distribution of the wave packet are evaluated. The effect of time parameters, amplitude, and number of HCPs on spatial and energy distribution of the final state and transfer efficiency are investigated. After a carefully tailored HCPs sequence is applied to the initial wave packet localized in one well, the final state is a wave packet localized in the other well and populated at the lower energy levels with narrower distribution. The present scheme could be used to control molecular reactions and to prepare atoms with large dipole moments.

Maximum gravitational-wave energy emissible in magnetar flares

Science.gov (United States)

Corsi, Alessandra; Owen, Benjamin J.

2011-05-01

Recent searches of gravitational-wave data raise the question of what maximum gravitational-wave energies could be emitted during gamma-ray flares of highly magnetized neutron stars (magnetars). The highest energies (˜1049erg) predicted so far come from a model [K. Ioka, Mon. Not. R. Astron. Soc.MNRAA40035-8711 327, 639 (2001), http://adsabs.harvard.edu/abs/2001MNRAS.327..639I] in which the internal magnetic field of a magnetar experiences a global reconfiguration, changing the hydromagnetic equilibrium structure of the star and tapping the gravitational potential energy without changing the magnetic potential energy. The largest energies in this model assume very special conditions, including a large change in moment of inertia (which was observed in at most one flare), a very high internal magnetic field, and a very soft equation of state. Here we show that energies of 1048-1049erg are possible under more generic conditions by tapping the magnetic energy, and we note that similar energies may also be available through cracking of exotic solid cores. Current observational limits on gravitational waves from magnetar fundamental modes are just reaching these energies and will beat them in the era of advanced interferometers.

Maximum gravitational-wave energy emissible in magnetar flares

International Nuclear Information System (INIS)

Corsi, Alessandra; Owen, Benjamin J.

2011-01-01

Recent searches of gravitational-wave data raise the question of what maximum gravitational-wave energies could be emitted during gamma-ray flares of highly magnetized neutron stars (magnetars). The highest energies (∼10 49 erg) predicted so far come from a model [K. Ioka, Mon. Not. R. Astron. Soc. 327, 639 (2001), http://adsabs.harvard.edu/abs/2001MNRAS.327..639I] in which the internal magnetic field of a magnetar experiences a global reconfiguration, changing the hydromagnetic equilibrium structure of the star and tapping the gravitational potential energy without changing the magnetic potential energy. The largest energies in this model assume very special conditions, including a large change in moment of inertia (which was observed in at most one flare), a very high internal magnetic field, and a very soft equation of state. Here we show that energies of 10 48 -10 49 erg are possible under more generic conditions by tapping the magnetic energy, and we note that similar energies may also be available through cracking of exotic solid cores. Current observational limits on gravitational waves from magnetar fundamental modes are just reaching these energies and will beat them in the era of advanced interferometers.

Prospects and applicability of wave energy for South Africa

Science.gov (United States)

Lavidas, George; Venugopal, Vengatesan

2018-03-01

Renewable energy offers significant opportunities for electricity diversification. South Africa belongs to the group of developing nations and encompasses a lot of potential for renewable energy developments. Currently, the majority of its electricity production originates from fossil fuels; however, incorporation of clean coal technologies will aid in reaching the assigned targets. This study offers a long-term wave power quantification analysis with a numerical wave model. The investigation includes long-term resource assessment in the region, variability, seasonal and monthly wave energy content. Locations with high-energy content but low variability pose an opportunity that can contribute in the alleviation of energy poverty. Application of wave converters depends on the combination of complex terms. The study presents resource levels and the joint distributions, which indicate suitability for converter selection. Depending on the region of interest, these characteristics change. Thus, this resource assessment adds knowledge on wave power and optimal consideration for wave energy applicability.

Surface wave energy absorption by a partially submerged bio-inspired canopy.

Science.gov (United States)

Nové-Josserand, C; Castro Hebrero, F; Petit, L-M; Megill, W M; Godoy-Diana, R; Thiria, B

2018-03-27

Aquatic plants are known to protect coastlines and riverbeds from erosion by damping waves and fluid flow. These flexible structures absorb the fluid-borne energy of an incoming fluid by deforming mechanically. In this paper we focus on the mechanisms involved in these fluid-elasticity interactions, as an efficient energy harvesting system, using an experimental canopy model in a wave tank. We study an array of partially-submerged flexible structures that are subjected to the action of a surface wave field, investigating in particular the role of spacing between the elements of the array on the ability of our system to absorb energy from the flow. The energy absorption potential of the canopy model is examined using global wave height measurements for the wave field and local measurements of the elastic energy based on the kinematics of each element of the canopy. We study different canopy arrays and show in particular that flexibility improves wave damping by around 40%, for which half is potentially harvestable.

Fully nonlinear time-domain simulation of a backward bent duct buoy floating wave energy converter using an acceleration potential method

Directory of Open Access Journals (Sweden)

Kyoung-Rok Lee

2013-12-01

Full Text Available A floating Oscillating Water Column (OWC wave energy converter, a Backward Bent Duct Buoy (BBDB, was simulated using a state-of-the-art, two-dimensional, fully-nonlinear Numerical Wave Tank (NWT technique. The hydrodynamic performance of the floating OWC device was evaluated in the time domain. The acceleration potential method, with a full-updated kernel matrix calculation associated with a mode decomposition scheme, was implemented to obtain accurate estimates of the hydrodynamic force and displacement of a freely floating BBDB. The developed NWT was based on the potential theory and the boundary element method with constant panels on the boundaries. The mixed Eulerian-Lagrangian (MEL approach was employed to capture the nonlinear free surfaces inside the chamber that interacted with a pneumatic pressure, induced by the time-varying airflow velocity at the air duct. A special viscous damping was applied to the chamber free surface to represent the viscous energy loss due to the BBDB's shape and motions. The viscous damping coefficient was properly selected using a comparison of the experimental data. The calculated surface elevation, inside and outside the chamber, with a tuned viscous damping correlated reasonably well with the experimental data for various incident wave conditions. The conservation of the total wave energy in the computational domain was confirmed over the entire range of wave frequencies.

Parametrization of the scattering wave functions of the Paris potential

International Nuclear Information System (INIS)

Loiseau, B.; Mathelitsch, L.

1996-10-01

The neutron-proton scattering wave functions of the Paris nucleon-nucleon potential are parametrized for partial waves of total angular momenta less than 5. The inner parts of the wave functions are approximated by polynomials with a continuous transition to the outer parts, which are given by the asymptotic regime and determined by the respective phase shifts. The scattering wave functions can then be calculated at any given energy below 400 MeV. Special attention is devoted to the zero-energy limit of the low partial waves. An easy-to-use FORTRAN program, which allows the user to calculate these parametrized wave functions, is available via electronic mail. (author)

Physical measurements of breaking wave impact on a floating wave energy converter

Science.gov (United States)

Hann, Martyn R.; Greaves, Deborah M.; Raby, Alison

2013-04-01

Marine energy converter must both efficiently extract energy in small to moderate seas and also successfully survive storms and potential collisions. Extreme loads on devices are therefore an important consideration in their design process. X-MED is a SuperGen UKCMER project and is a collaboration between the Universities of Manchester, Edinburgh and Plymouth and the Scottish Association for Marine Sciences. Its objective is to extend the knowledge of extreme loads due to waves, currents, flotsam and mammal impacts. Plymouth Universities contribution to the X-MED project involves measuring the loading and response of a taut moored floating body due to steep and breaking wave impacts, in both long crested and directional sea states. These measurements are then to be reproduced in STAR-CCM+, a commercial volume of fluid CFD solver, so as to develop techniques to predict the wave loading on wave energy converters. The measurements presented here were conducted in Plymouth Universities newly opened COAST laboratories 35m long, 15.5m wide and 3m deep ocean basin. A 0.5m diameter taut moored hemispherical buoy was used to represent a floating wave energy device or support structure. The changes in the buoys 6 degree of freedom motion and mooring loads are presented due to focused breaking wave impacts, with the breaking point of the wave changed relative to the buoy.

Further development of the SEA-Clam wave energy converter

Energy Technology Data Exchange (ETDEWEB)

Bellamy, N.W.; Peatfield, A.M.

1984-04-01

The final design of the SEA-Clam as a unit for a large 2 GW scheme has been described. This is the leading wave energy device arising out of the UK National Wave Energy Program and is seen as having the greatest potential for further development particularly for smaller scale applications. The small scale market for wave energy is examined and the design and cost parameters evaluated for the 250 kW to 1000 kW range of SEA-Clam units. Building a demonstration prototype rated at 650 kW and producing an annual average output of 250 kW is identified as the next step towards the commercial exploitation of wave energy.

Numerical Modeling of a Wave Energy Point Absorber

DEFF Research Database (Denmark)

Hernandez, Lorenzo Banos; Frigaard, Peter; Kirkegaard, Poul Henning

2009-01-01

The present study deals with numerical modelling of the Wave Star Energy WSE device. Hereby, linear potential theory is applied via a BEM code on the wave hydrodynamics exciting the floaters. Time and frequency domain solutions of the floater response are determined for regular and irregular seas....... Furthermore, these results are used to estimate the power and the energy absorbed by a single oscillating floater. Finally, a latching control strategy is analysed in open-loop configuration for energy maximization....

Wave energy for the 21st century: status and prospects

International Nuclear Information System (INIS)

Thorpe, Tom

2000-01-01

This article reviews the current technical and commercial status of wave energy, and discusses the design of near shore devices such as the 2MW OSPREY, and offshore devices including the McCabe wave pump, the Ocean Power Technology Wave Energy Converter, the Archimedes Wave Swing, the Pelamis, and wave energy schemes under development by other commercial firms. The predicted generating costs, the potential market, environmental impacts, and institution factors such as planning and consent, grid connection,and safety in design and operation are considered. The operating principles of an oscillating water column, and some promising offshore devices are illustrated

Colloquium: Multimessenger astronomy with gravitational waves and high-energy neutrinos

NARCIS (Netherlands)

Ando, S.; Baret, B.; Bartos, I.; Bouhou, B.; Chassande-Mottin, E.; Corsi, A.; Di Palma, I.; Dietz, A.; Donzaud, C.; Eichler, D.; Finley, C.; Guetta, D.; Halzen, F.; Jones, G.; Kandhasamy, S.; Kotake, K.; Kouchner, A.; Mandic, V.; Márka, S.; Márka, Z.; Moscoso, L.; Papa, M.A.; Piran, T.; Pradier, T.; Romero, G.E.; Sutton, P.; Thrane, E.; van Elewyck, V.; Waxman, E.

2013-01-01

Many of the astrophysical sources and violent phenomena observed in our Universe are potential emitters of gravitational waves and high-energy cosmic radiation, including photons, hadrons, and presumably also neutrinos. Both gravitational waves (GW) and high-energy neutrinos (HEN) are cosmic

The Wave Energy Sector

DEFF Research Database (Denmark)

Kofoed, Jens Peter

2017-01-01

This Handbook for Ocean Wave Energy aims at providing a guide into the field of ocean wave energy utilization. The handbook offers a concise yet comprehensive overview of the main aspects and disciplines involved in the development of wave energy converters (WECs). The idea for the book has been...... shaped by the development, research, and teaching that we have carried out at the Wave Energy Research Group at Aalborg University over the past decades. It is our belief and experience that it would be useful writing and compiling such a handbook in order to enhance the understanding of the sector...

Simulation of breaking waves using the high-order spectral method with laboratory experiments: wave-breaking energy dissipation

Science.gov (United States)

Seiffert, Betsy R.; Ducrozet, Guillaume

2018-01-01

We examine the implementation of a wave-breaking mechanism into a nonlinear potential flow solver. The success of the mechanism will be studied by implementing it into the numerical model HOS-NWT, which is a computationally efficient, open source code that solves for the free surface in a numerical wave tank using the high-order spectral (HOS) method. Once the breaking mechanism is validated, it can be implemented into other nonlinear potential flow models. To solve for wave-breaking, first a wave-breaking onset parameter is identified, and then a method for computing wave-breaking associated energy loss is determined. Wave-breaking onset is calculated using a breaking criteria introduced by Barthelemy et al. (J Fluid Mech https://arxiv.org/pdf/1508.06002.pdf, submitted) and validated with the experiments of Saket et al. (J Fluid Mech 811:642-658, 2017). Wave-breaking energy dissipation is calculated by adding a viscous diffusion term computed using an eddy viscosity parameter introduced by Tian et al. (Phys Fluids 20(6): 066,604, 2008, Phys Fluids 24(3), 2012), which is estimated based on the pre-breaking wave geometry. A set of two-dimensional experiments is conducted to validate the implemented wave breaking mechanism at a large scale. Breaking waves are generated by using traditional methods of evolution of focused waves and modulational instability, as well as irregular breaking waves with a range of primary frequencies, providing a wide range of breaking conditions to validate the solver. Furthermore, adjustments are made to the method of application and coefficient of the viscous diffusion term with negligible difference, supporting the robustness of the eddy viscosity parameter. The model is able to accurately predict surface elevation and corresponding frequency/amplitude spectrum, as well as energy dissipation when compared with the experimental measurements. This suggests the model is capable of calculating wave-breaking onset and energy dissipation

Design guidelines of triboelectric nanogenerator for water wave energy harvesters

KAUST Repository

Ahmed, Abdelsalam

2017-04-11

Ocean waves are one of the cleanest and most abundant energy sources on earth, and wave energy has the potential for future power generation. Triboelectric nanogenerator (TENG) technology has recently been proposed as a promising technology to harvest wave energy. In this paper, a theoretical study is performed on a duck-shaped TENG wave harvester recently introduced in our work. To enhance the design of the duck-shaped TENG wave harvester, the mechanical and electrical characteristics of the harvester\\'s overall structure, as well as its inner configuration, are analyzed, respectively, under different wave conditions, to optimize parameters such as duck radius and mass. Furthermore, a comprehensive hybrid 3D model is introduced to quantify the performance of the TENG wave harvester. Finally, the influence of different TENG parameters is validated by comparing the performance of several existing TENG wave harvesters. This study can be applied as a guideline for enhancing the performance of TENG wave energy harvesters.

Design guidelines of triboelectric nanogenerator for water wave energy harvesters

KAUST Repository

Ahmed, Abdelsalam; Hassan, Islam; Jiang, Tao; Youssef, Khalid; Liu, Lian; Hedaya, Mohammad; Yazid, Taher Abu; Zu, Jean; Wang, Zhong Lin

2017-01-01

Ocean waves are one of the cleanest and most abundant energy sources on earth, and wave energy has the potential for future power generation. Triboelectric nanogenerator (TENG) technology has recently been proposed as a promising technology to harvest wave energy. In this paper, a theoretical study is performed on a duck-shaped TENG wave harvester recently introduced in our work. To enhance the design of the duck-shaped TENG wave harvester, the mechanical and electrical characteristics of the harvester's overall structure, as well as its inner configuration, are analyzed, respectively, under different wave conditions, to optimize parameters such as duck radius and mass. Furthermore, a comprehensive hybrid 3D model is introduced to quantify the performance of the TENG wave harvester. Finally, the influence of different TENG parameters is validated by comparing the performance of several existing TENG wave harvesters. This study can be applied as a guideline for enhancing the performance of TENG wave energy harvesters.

Design guidelines of triboelectric nanogenerator for water wave energy harvesters.

Science.gov (United States)

Ahmed, Abdelsalam; Hassan, Islam; Jiang, Tao; Youssef, Khalid; Liu, Lian; Hedaya, Mohammad; Yazid, Taher Abu; Zu, Jean; Wang, Zhong Lin

2017-05-05

Ocean waves are one of the cleanest and most abundant energy sources on earth, and wave energy has the potential for future power generation. Triboelectric nanogenerator (TENG) technology has recently been proposed as a promising technology to harvest wave energy. In this paper, a theoretical study is performed on a duck-shaped TENG wave harvester recently introduced in our work. To enhance the design of the duck-shaped TENG wave harvester, the mechanical and electrical characteristics of the harvester's overall structure, as well as its inner configuration, are analyzed, respectively, under different wave conditions, to optimize parameters such as duck radius and mass. Furthermore, a comprehensive hybrid 3D model is introduced to quantify the performance of the TENG wave harvester. Finally, the influence of different TENG parameters is validated by comparing the performance of several existing TENG wave harvesters. This study can be applied as a guideline for enhancing the performance of TENG wave energy harvesters.

Probing potential energy curves of C2- by translational energy spectrometry

International Nuclear Information System (INIS)

Gupta, A.K.; Aravind, G.; Krishnamurthy, M.

2004-01-01

We present studies on collision induced dissociation of C 2 - with Ar at an impact energy of 15 keV. The C - fragment ion kinetic-energy release (KER) distribution is measured and is used to compute the KER in the center of mass (c.m.) frame (KER c.m. ). We employ the reflection method to deduce an effective repulsive potential-energy curve for the molecular anion that is otherwise difficult to evaluate from quantum computational methods. The nuclear wave packet of the molecular ion in the initial ground state is computed by the semiclassical WKB method using the potential-energy curve of the 2 Σ g + ground electronic state calculated by an ab initio quantum computation method. The ground-state nuclear wave packet is reflected on a parametrized repulsive potential-energy curve where the parameters are determined by fitting the measured KER c.m. with the calculated KER distribution

Fundamental formulae for wave-energy conversion.

Science.gov (United States)

Falnes, Johannes; Kurniawan, Adi

2015-03-01

The time-average wave power that is absorbed from an incident wave by means of a wave-energy conversion (WEC) unit, or by an array of WEC units-i.e. oscillating immersed bodies and/or oscillating water columns (OWCs)-may be mathematically expressed in terms of the WEC units' complex oscillation amplitudes, or in terms of the generated outgoing (diffracted plus radiated) waves, or alternatively, in terms of the radiated waves alone. Following recent controversy, the corresponding three optional expressions are derived, compared and discussed in this paper. They all provide the correct time-average absorbed power. However, only the first-mentioned expression is applicable to quantify the instantaneous absorbed wave power and the associated reactive power. In this connection, new formulae are derived that relate the 'added-mass' matrix, as well as a couple of additional reactive radiation-parameter matrices, to the difference between kinetic energy and potential energy in the water surrounding the immersed oscillating WEC array. Further, a complex collective oscillation amplitude is introduced, which makes it possible to derive, by a very simple algebraic method, various simple expressions for the maximum time-average wave power that may be absorbed by the WEC array. The real-valued time-average absorbed power is illustrated as an axisymmetric paraboloid defined on the complex collective-amplitude plane. This is a simple illustration of the so-called 'fundamental theorem for wave power'. Finally, the paper also presents a new derivation that extends a recently published result on the direction-average maximum absorbed wave power to cases where the WEC array's radiation damping matrix may be singular and where the WEC array may contain OWCs in addition to oscillating bodies.

Handbook of Ocean Wave Energy

DEFF Research Database (Denmark)

This book offers a concise, practice-oriented reference-guide to the field of ocean wave energy. The ten chapters highlight the key rules of thumb, address all the main technical engineering aspects and describe in detail all the key aspects to be considered in the techno-economic assessment...... in the wave energy sector. •Offers a practice-oriented reference guide to the field of ocean wave energy •Presents an overview as well as a deeper insight into wave energy converters •Covers both the economic and engineering aspects related to ocean wave energy conversion...... of wave energy converters. Written in an easy-to-understand style, the book answers questions relevant to readers of different backgrounds, from developers, private and public investors, to students and researchers. It is thereby a valuable resource for both newcomers and experienced practitioners...

Handbook of Ocean Wave Energy

DEFF Research Database (Denmark)

This book offers a concise, practice-oriented reference-guide to the field of ocean wave energy. The ten chapters highlight the key rules of thumb, address all the main technical engineering aspects and describe in detail all the key aspects to be considered in the techno-economic assessment...... of wave energy converters. Written in an easy-to-understand style, the book answers questions relevant to readers of different backgrounds, from developers, private and public investors, to students and researchers. It is thereby a valuable resource for both newcomers and experienced practitioners...... in the wave energy sector. •Offers a practice-oriented reference guide to the field of ocean wave energy •Presents an overview as well as a deeper insight into wave energy converters •Covers both the economic and engineering aspects related to ocean wave energy conversion...

On the Quantum Potential and Pulsating Wave Packet in the Harmonic Oscillator

International Nuclear Information System (INIS)

Dubois, Daniel M.

2008-01-01

A fundamental mathematical formalism related to the Quantum Potential factor, Q, is presented in this paper. The Schroedinger equation can be transformed to two equations depending on a group velocity and a density of presence of the particle. A factor, in these equations, was called ''Quantum Potential'' by D. Bohm and B. Hiley. In 1999, I demonstrated that this Quantum Potential, Q, can be split in two Quantum Potentials, Q 1 , and Q 2 , for which the relation, Q=Q 1 +Q 2 , holds. These two Quantum Potentials depend on a fundamental new variable, what I called a phase velocity, u, directly related to the probability density of presence of the wave-particle, given by the modulus of the wave function. This paper gives some further developments for explaining the Quantum Potential for oscillating and pulsating Gaussian wave packets in the Harmonic Oscillator. It is shown that the two Quantum Potentials play a central role in the interpretation of quantum mechanics. A breakthrough in the formalism of the Quantum Mechanics could be provoked by the physical properties of these Quantum Potentials. The probability density of presence of the oscillating and pulsating Gaussian wave packets in the Harmonic Oscillator is directly depending on the ratio Q 2 /Q 1 of the two Quantum Potentials. In the general case, the energy of these Gaussian wave packets is not constant, but is oscillating. The energy is given by the sum of the kinetic energy, T, the potential energy, V, and the two Quantum Potentials: E=T+V+Q 1 +Q 2 . For some conditions, given in the paper, the energy can be a constant. The first remarkable result is the fact that the first Quantum Potential, Q 1 , is related to the ground state energy, E 0 , of the Quantum Harmonic Oscillator: Q 1 =h-bar ω/2=E 0 . The second result is related to the property of the second Quantum Potential, Q 2 , which plays the role of an anti-potential, Q 2 =-V(x), where V is the harmonic oscillator potential. This Quantum Potential

Wave energy converter effects on wave propagation: A sensitivity study in Monterey Bay, CA

Science.gov (United States)

Chang, G.; Jones, C. A.; Roberts, J.; Magalen, J.; Ruehl, K.; Chartrand, C.

2014-12-01

The development of renewable offshore energy in the United States is growing rapidly and wave energy is one of the largest resources currently being evaluated. The deployment of wave energy converter (WEC) arrays required to harness this resource could feasibly number in the hundreds of individual devices. The WEC arrays have the potential to alter nearshore wave propagation and circulation patterns and ecosystem processes. As the industry progresses from pilot- to commercial-scale it is important to understand and quantify the effects of WECs on the natural nearshore processes that support a local, healthy ecosystem. To help accelerate the realization of commercial-scale wave power, predictive modeling tools have been developed and utilized to evaluate the likelihood of environmental impact. At present, direct measurements of the effects of different types of WEC arrays on nearshore wave propagation are not available; therefore wave model simulations provide the groundwork for investigations of the sensitivity of model results to prescribed WEC characteristics over a range of anticipated wave conditions. The present study incorporates a modified version of an industry standard wave modeling tool, SWAN (Simulating WAves Nearshore), to simulate wave propagation through a hypothetical WEC array deployment site on the California coast. The modified SWAN, referred to as SNL-SWAN, incorporates device-specific WEC power take-off characteristics to more accurately evaluate a WEC device's effects on wave propagation. The primary objectives were to investigate the effects of a range of WEC devices and device and array characteristics (e.g., device spacing, number of WECs in an array) on nearshore wave propagation using SNL-SWAN model simulations. Results showed that significant wave height was most sensitive to variations in WEC device type and size and the number of WEC devices in an array. Locations in the lee centerline of the arrays in each modeled scenario showed the

The environmental interactions of tidal and wave energy generation devices

International Nuclear Information System (INIS)

Frid, Chris; Andonegi, Eider; Depestele, Jochen; Judd, Adrian; Rihan, Dominic; Rogers, Stuart I.; Kenchington, Ellen

2012-01-01

Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other offshore energy developments is lacking. Tidal barrages have the potential to cause significant ecological impacts particularly on bird feeding areas when they are constructed at coastal estuaries or bays. Offshore tidal stream energy and wave energy collectors offer the scope for developments at varying scales. They also have the potential to alter habitats. A diversity of designs exist, including floating, mid-water column and seabed mounted devices, with a variety of moving-part configurations resulting in a unique complex of potential environmental effects for each device type, which are discussed to the extent possible. - Highlights: ► We review the environmental impacts of tidal barrages and fences, tidal stream farms and wave energy capture devices. ► Impacts on habitats, species and the water column, and effects of noise and electromagnetic fields are considered. ► Tidal barrages can cause significant impacts on bird feeding areas when constructed at coastal estuaries or bays. ► Wave energy collectors can alter water column and sea bed habitats locally and over large distances.

The environmental interactions of tidal and wave energy generation devices

Energy Technology Data Exchange (ETDEWEB)

Frid, Chris, E-mail: c.l.j.frid@liv.ac.uk [School of Environmental Sciences, University of Liverpool, Crown Street, Liverpool, L69 7ZB (United Kingdom); Andonegi, Eider, E-mail: eandonegi@azti.es [AZTI-Tecnalia, Txatxarramendi ugartea, z/g E-48395 Sukarrieta (Bizkaia) (Spain); Depestele, Jochen, E-mail: jochen.depestele@ilvo.vlaanderen.be [Institute for Agricultural and Fisheries Research, Ankerstraat 1, B-8400 Oostende (Belgium); Judd, Adrian, E-mail: Adrian.Judd@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science , Lowestoft Laboratory, Pakefield Road, Lowestoft NR33 0HT United Kingdom (United Kingdom); Rihan, Dominic, E-mail: Dominic.RIHAN@ec.europa.eu [Irish Sea Fisheries Board, P.O. Box 12 Dun Laoghaire, Co. Dublin (Ireland); Rogers, Stuart I., E-mail: stuart.rogers@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science , Lowestoft Laboratory, Pakefield Road, Lowestoft NR33 0HT United Kingdom (United Kingdom); Kenchington, Ellen, E-mail: Ellen.Kenchington@dfo-mpo.gc.ca [Fisheries and Oceans Canada, Bedford Institute of Oceanography, P.O. Box 1006, Dartmouth Canada, NS B2Y 4A2 (Canada)

2012-01-15

Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other offshore energy developments is lacking. Tidal barrages have the potential to cause significant ecological impacts particularly on bird feeding areas when they are constructed at coastal estuaries or bays. Offshore tidal stream energy and wave energy collectors offer the scope for developments at varying scales. They also have the potential to alter habitats. A diversity of designs exist, including floating, mid-water column and seabed mounted devices, with a variety of moving-part configurations resulting in a unique complex of potential environmental effects for each device type, which are discussed to the extent possible. - Highlights: Black-Right-Pointing-Pointer We review the environmental impacts of tidal barrages and fences, tidal stream farms and wave energy capture devices. Black-Right-Pointing-Pointer Impacts on habitats, species and the water column, and effects of noise and electromagnetic fields are considered. Black-Right-Pointing-Pointer Tidal barrages can cause significant impacts on bird feeding areas when constructed at coastal estuaries or bays. Black-Right-Pointing-Pointer Wave energy collectors can alter water column and sea bed habitats locally and over large distances.

Optimized Latching Control of Floating Point Absorber Wave Energy Converter

Science.gov (United States)

Gadodia, Chaitanya; Shandilya, Shubham; Bansal, Hari Om

2018-03-01

There is an increasing demand for energy in today’s world. Currently main energy resources are fossil fuels, which will eventually drain out, also the emissions produced from them contribute to global warming. For a sustainable future, these fossil fuels should be replaced with renewable and green energy sources. Sea waves are a gigantic and undiscovered vitality asset. The potential for extricating energy from waves is extensive. To trap this energy, wave energy converters (WEC) are needed. There is a need for increasing the energy output and decreasing the cost requirement of these existing WECs. This paper presents a method which uses prediction as a part of the control scheme to increase the energy efficiency of the floating-point absorber WECs. Kalman Filter is used for estimation, coupled with latching control in regular as well as irregular sea waves. Modelling and Simulation results for the same are also included.

Experimental Validation of a Wave Energy Converter Array Hydrodynamics Tool

DEFF Research Database (Denmark)

Ruiz, Pau Mercadé; Ferri, Francesco; Kofoed, Jens Peter

2017-01-01

This paper uses experimental data to validate a wave energy converter (WEC) array hydrodynamics tool developed within the context of linearized potential flow theory. To this end, wave forces and power absorption by an array of five-point absorber WECs in monochromatic and panchromatic waves were...

Strengths-weaknesses-opportunities-threats (Swot) of wave energy industry in Portugal

International Nuclear Information System (INIS)

La regina, Veronica; Neumann, Frank; Russell, Iain; Sarmento, Antonio J. N. A.

2006-01-01

Energy policy-makers in countries are facing the daunting challenge of achieving energy security environmental protection and economic efficie16ncy. Renewable are considered by many policy-makers to contribute to improving energy security and protecting the environment. On an average cost basis, some renewables in the best locations are still not competitive. Supportive policies are still needed to encourage the further development and deployment especially of 'new' renewables in energy markets. Wave energy (WE) is front-runner of Marine Renewable Energies, as its technologies are not yet mature for a complete commercial status. Thus, a new a potential wave energy industry requires strong policy support from all stakeholders involved in it. We, like most other forms of renewable energy (RE), has a significant potential to mitigate global climate change, address regional and local environmental concerne, reduce poverty and increase energy security. The challenge is to provide the right policy frameworks and financial tools that will enable RE to achieve its market potential and move from marginal significance for the energy supply into the mainstream. Policy-makers thus have a mandate to take action and, since most of the capital for these green-actions will not come from public treasuries, most of these actions will need to focus on creating enabling frameworks and finance mechanisms for technology R and D, commercialisation and investment. For this form of RE to achieve its market potential, policy frameworks and financial instruments are necessary that give financiers the necessary assurance and incentives to shift investment away from oil technologies to large-scale investment in a clean energy systems. The paper assesses how Portugal should result attractive for wave energy industry according with geographical position, wave motions' power and policies' ability to attract finance. It describes present financing instruments for wave energy plant development and

Deployment Effects of Marine Renewable Energy Technologies: Wave Energy Scenarios

Energy Technology Data Exchange (ETDEWEB)

Mirko Previsic

2010-06-17

Given proper care in siting, design, deployment, operation and maintenance, wave energy conversion could become one of the more environmentally benign sources of electricity generation. In order to accelerate the adoption of these emerging hydrokinetic and marine energy technologies, navigational and environmental concerns must be identified and addressed. All developing hydrokinetic projects involve a wide variety of stakeholders. One of the key issues that site developers face as they engage with this range of stakeholders is that, due to a lack of technical certainty, many of the possible conflicts (e.g., shipping and fishing) and environmental issues are not well-understood,. In September 2008, re vision consulting, LLC was selected by the Department of Energy (DoE) to apply a scenario-based assessment to the emerging hydrokinetic technology sector in order to evaluate the potential impact of these technologies on the marine environment and navigation constraints. The project’s scope of work includes the establishment of baseline scenarios for wave and tidal power conversion at potential future deployment sites. The scenarios capture variations in technical approaches and deployment scales to properly identify and characterize environmental effects and navigational effects. The goal of the project is to provide all stakeholders with an improved understanding of the potential range of technical attributes and potential effects of these emerging technologies and focus all stakeholders on the critical issues that need to be addressed. By identifying and addressing navigational and environmental concerns in the early stages of the industry’s development, serious mistakes that could potentially derail industry-wide development can be avoided. This groundwork will also help in streamlining siting and associated permitting processes, which are considered key hurdles for the industry’s development in the U.S. today. Re vision is coordinating its efforts with two

Wave power integration with a renewable hydrogen energy system. Paper no. IGEC-1-085

International Nuclear Information System (INIS)

St. Germain, L.; Wild, P.; Rowe, A.

2005-01-01

In British Columbia, approximately 90% of the electricity generated comes from hydroelectric facilities while another abundant and renewable resource, ocean wave energy, is not being utilized at all. Technologies exist that can capture and convert wave energy but there are few studies examining systemic integration of wave energy devices. This work examines the potential to use wave energy as an input into a hydrogen-based renewable energy system. A model of an oscillating water column (OWC) was developed as a module within TRNSYS where it can be coupled to other existing hydrogen-specific components such as an electrolyser, storage device, and fuel cell. The OWC model accounts for device geometry, dynamics, and generator efficiency. For this particular study, wave profiles generated from hourly average data for a location on the west coast of Vancouver Island are used as a resource input. An analysis of the potential to utilise wave energy is carried out with an emphasis on overall system efficiency and resulting device scaling. The results of the integration of wave energy with other renewable energy inputs into a hydrogen-based system are used to make recommendations regarding technical feasibility of wave power projects on Vancouver Island. (author)

Wave Energy Converters based on Dielectric Elastomer generators: Status and perspectives

International Nuclear Information System (INIS)

Fontana, Marco; Vertechy, Rocco

2015-01-01

Dielectric Elastomers (DEs) are a very promising technology for the development of energy harvesting devices based on the variable-capacitance electrostatic generator principle. This paper discusses the potentialities of DE technology for advancing the ocean wave energy sector. In particular, three innovative concepts of wave energy converters with DE-based power take-off system are introduced and described.

Development of the Wave Energy Converter -Wave Dragon

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter; Sørensen, Hans Christian

2000-01-01

2Over the years wave energy has gradually been brought into focus, as it has become clear that the fossil energy resources are limited, and cause large environmental problems, e.g. CO2 pollution. On this background a number of different wave energy converters have been proposed. In Denmark the go...

Energy supply technologies. Hydro, ocean, wave and tidal

Energy Technology Data Exchange (ETDEWEB)

Fenhann, J.; Larsen, Hans [Risoe National Lab. - DTU (Denmark)

2007-11-15

This chapter presents an overview of current hydro, ocean, wave and tidal initiatives. Large hydro remains one of the lowest-cost generating technologies, although environmental constraints, resettlement impacts and the limited availability of sites have restricted further growth in many countries. Large hydro supplied 16 % of global electricity in 2004, down from 19 % a decade ago. Large hydro capacity totalled about 720 GW worldwide in 2004 and has grown historically at slightly more than 2 % annually. China installed nearly 8 GW of large hydro in 2004, taking the country to number one in terms of installed capacity (74 GW). With the completion of the Three Gorges Dam, China will add some 18.2 GW of hydro capacity in 2009. The socio-economic benefits of hydro include improved flood control and water supply. The socio-economic benefits of hydro include improved flood control and water supply. The socio-economic cost of hydro includes displacements and submergence. Further hydro can improve peak-capacity management. Ocean currents, some of which runs close to European coasts, carry a lot of kinetic energy. Part of this energy can be captured by sub-marine windmills and converted into electricity. These are more compact than the wind turbines used on land, simply because water is much denser than air. The main European countries with useful current power potential are France and the UK. Ocean tides are driven by the gravitational pull of the moon. With one high tide every 12 hours, a tidal power plant can operate for only four or five hours per cycle, so power from a single plant is intermittent. A suitably-designed tidal plant can, however, operate as a pimped storage system, using electricity during periods of low demand to store energy that can be recovered later. The only large, modern example of a tidal power plant is the 240 MW La Rance plant, built in France in the 1960s, which represents 91 % of the world tidal power capacity. Wave energy can be seen as

Hanstholm phase 2B. Offshore wave energy test 1994 - 1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-11-01

The wave power converter consists of a float 2.5 meter in diameter, connected by a rope to a seabed-mounted piston pump, installed on 25 meter deep water 2,5 km offshore Hanstholm, Denmark. The converter is designed to absorb an average maximum power of 1 kW. Measured data in real sea conditions are compared to results based on computer simulations and previous tank testing. Losses caused by rope elasticity and hysteresis, friction in the pump and back flow through the valves are assessed. The economic perspectives of a large wave power plant are presented, based on a revised prototype incorporating the results and experience gained during the test period. The wave energy conversion test `Hanstholm phase 2B` has showed, that it it technically possible to exploit the offshore wave energy resource. This source of energy could become attractive for commercial enterprise. The wave power converter demonstrated a reliable performance over a period of nine months. It produced energy under all wave conditions and survived storm waves of 9,6 m. A 300 MW wave power plant in the Danish part of the North sea is estimated to produce electricity at a cost between 2,1 - 2,4 DKK/kWh. The electrical transmission to shore contribute to approximately 20% of the cost. New data predict a potential of 23 kW per meter wave front. The energy plan Energy 21 proposed by the Danish Department of Energy, includes a scenario incorporating wave energy in the energy system year 2030. A strategy for the development of wave energy, has been proposed as part of the project OWEC-1 supported by the European Joule R and D programme. A proposal for future Danish initiatives to develop second generation point absorber systems is outlined. (ARW) 29 refs.

Bound and scattering wave functions for a velocity-dependent Kisslinger potential for l>0

International Nuclear Information System (INIS)

Jaghoub, M.I.

2002-01-01

Using formal scattering theory, the scattering wave functions are extrapolated to negative energies corresponding to bound-state poles. It is shown that the ratio of the normalized scattering and the corresponding bound-state wave functions, at a bound-state pole, is uniquely determined by the bound-state binding energy. This simple relation is proved analytically for an arbitrary angular momentum quantum number l>0, in the presence of a velocity-dependent Kisslinger potential. The extrapolation relation is tested analytically by solving the Schroedinger equation in the p-wave case exactly for the scattering and the corresponding bound-state wave functions when the Kisslinger potential has the form of a square well. A numerical resolution of the Schroedinger equation in the p-wave case and of a square-well Kisslinger potential is carried out to investigate the range of validity of the extrapolated connection. It is found that the derived relation is satisfied best at low energies and short distances. (orig.)

Wave energy : from demonstration to commercialization

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-07-01

The Wave Energy Centre is a non-profit organization dedicated to the development and marketing of ocean wave energy devices through technical and strategic support to companies and research and development institutions. WEC provides access to researchers to associated test infrastructures for testing and demonstration of wave energy structures. This presentation described the current status of wave energy. Public policies that support wave energy were also highlighted. Wave energy technology is currently in the demonstration phase, with several pilot plants and prototypes in service around the world. The first 2 offshore shoreline ocean wave current pilot plants were constructed in 2000. This presentation identified the 12 near or offshore pilot plants that were in operation by 2007. The pilot plants represent 5 basic different concepts with many different designs. The world's first commercial park was launched in 2007 in Portugal. The Pelamis wave farm uses three Pelamis P-750 machines with a capacity of 2.25 megawatts. figs.

Wave and offshore wind potential for the island of Tenerife

International Nuclear Information System (INIS)

Veigas, M.; Iglesias, G.

2013-01-01

Highlights: • The island aims to reduce its carbon footprint by developing renewable energy. • The substantial wave and offshore wind resources around the island are examined. • One area is appropriate for installing a hybrid wave–offshore wind farm. - Abstract: The island of Tenerife, a UNESCO Biosphere Reserve in the Atlantic Ocean, aims to be energy self-sufficient in order to reduce its carbon footprint. To accomplish this goal it should develop the renewable sources, in particular wave and offshore wind energy. The objectives of this work are twofold; (i) to characterize the wave and offshore wind power distribution around the island and (ii) to determine which offshore area is best suited for their exploitation, taking into account the resource and other conditioning factors such as the bathymetry, distance to the coastline and ports, and offshore zoning. To carry out this research, hindcast wave and wind data obtained with numerical models are used alongside observations from meteorological stations. One area, in the vicinity of Puerto de la Cruz, is identified as having great potential for installing a hybrid floating wave–wind farm. Both resources are characterized for the area selected: the wave resource in terms of wave directions, significant wave heights and energy periods; the offshore wind resource in terms of directions and speeds in addition to the seasonality for the both resources. It is found that most of the wave resource is provided by N and NNW waves with significant wave heights between 1.5 m and 3.0 m and energy periods between 10 s and 14 s. It follows that the Wave Energy Converters deployed in the area should have maximum efficiency in those ranges. As for the offshore wind resource, most of the energy corresponds to NNE and NE winds with speeds between 9 and 14 m s −1 , which should be taken into account when selecting the offshore wind turbines

Wave energy fluxes and multi-decadal shoreline changes

DEFF Research Database (Denmark)

Kabuth, Alina Kristin; Kroon, Aart

2014-01-01

Spatial patterns of multidecadal shoreline changes in two microtidal, low-energetic embayments of southern Zealand, Denmark, were investigated by using the directional distribution of wave energy fluxes. The sites include a barrier island system attached to moraine bluffs, and a recurved spit...... variability of directional distributions of wave energy fluxes furthermore outlined potential sediment sources and sinks for the evolution of the barrier island system and for the evolution of the recurved spit....... adjacent to a cliff coast. The barrier island system is characterized by cross-shore translation and by an alignment of the barrier alongshore alternating directions of barrier-spit progradation in a bidirectional wave field. The recurved spit adjacent to the cliff coast experienced shoreline rotation...

Experiments on the WavePiston, Wave Energy Converter

DEFF Research Database (Denmark)

Angelelli, E.; Zanuttigh, B.; Kofoed, Jens Peter

2011-01-01

This paper analyses the performance of a new Wave Energy Converter (WEC) of the Oscillating Water Column type (OWC), named WavePiston. This near-shore floating device is composed of plates (i.e. energy collectors) sliding around a cylinder, that is placed perpendicular to the shore. Tests...... in the wave basin at Aalborg University allowed to investigate power production in the North Sea typical wave climate, with varying design parameters such as plate dimensions and their mutual distance. The power produced per meter by each collector is about the 5% of the available wave power. Experimental...... results and survivability considerations suggest that the WavePiston would be particularly suited for installations in milder seas. An example application is therefore presented in the Mediterranean Sea, off-shore the island of Sicily. In this case, each collector harvests the 10% of the available wave...

Licensing and Environmental Issues of Wave Energy Projects

DEFF Research Database (Denmark)

Neumann, Frank; Tedd, James; Prado, Miguel

2006-01-01

a special standing or facilitated access to operating licenses due to their experimental character, the move of wave energy projects towards commercial applications implies complex procedures for obtaining licenses both with respect to the construction and deployment and operation phases, as well......The major non-technical barrier for large-scale wave energy implementation is the wide range of licensing issues and potential environmental concerns, in addition to significant National/regional differences in licensing procedures and permit requirements. Whereas some pilot plants have had...... as concerning ocean space use and environmental concerns. Despite recent efforts to streamline European EIA (Environmental Impact Assessment) in general, potential project developers are far from having a clear view of present and future requirements concerning these barriers on a trans-national level...

A 35 year high-resolution wave atlas for nearshore energy production and economics at the Aegean Sea

OpenAIRE

Lavidas, George; Venugopal, Vengatesan

2017-01-01

The study enhances the coastal resource knowledge and discusses opportunities for wave energy in theAegean Sea. A fine-resolution numerical wave model is utilised to provide results for the Greek coastalregions. The model ran for 35 years (1980e2014) estimating wave characteristics, and quantifying thewave energy potential in coastal areas. The results deliver the energy potential, variability, and sitecharacterisation for the Aegean Sea.The dataset is coupled with wave energy converters powe...

Assessment of theoretical near-shore wave power potential along the Lithuanian coast of the Baltic Sea

DEFF Research Database (Denmark)

Kasiulis, E; Punys, P; Kofoed, Jens Peter

2015-01-01

is evaluated using available multi-year visual observation data. A brief review of European wave energy resources, focusing more on semi-enclosed seas, is provided, as well as a comparison between wave energy potential and conventional hydropower potential in European countries. A conventional hydrological...

Wave energy input into the Ekman layer

Institute of Scientific and Technical Information of China (English)

2008-01-01

This paper is concerned with the wave energy input into the Ekman layer, based on 3 observational facts that surface waves could significantly affect the profile of the Ekman layer. Under the assumption of constant vertical diffusivity, the analytical form of wave energy input into the Ekman layer is derived. Analysis of the energy balance shows that the energy input to the Ekman layer through the wind stress and the interaction of the Stokes-drift with planetary vorticity can be divided into two kinds. One is the wind energy input, and the other is the wave energy input which is dependent on wind speed, wave characteristics and the wind direction relative to the wave direction. Estimates of wave energy input show that wave energy input can be up to 10% in high-latitude and high-wind speed areas and higher than 20% in the Antarctic Circumpolar Current, compared with the wind energy input into the classical Ekman layer. Results of this paper are of significance to the study of wave-induced large scale effects.

Wave energy

Energy Technology Data Exchange (ETDEWEB)

Whittaker, T.J.T. (Queen' s Univ., Belfast, Northern Ireland (UK)); White, P.R.S. (Lanchester Polytechnic, Coventry (UK)); Baker, A.C.J. (Binnie and Partners, London (UK))

1988-10-01

An informal discussion on various wave energy converters is reported. These included a prototype oscillating water column (OWC) device being built on the Isle of Islay in Scotland; the SEA Clam; a tapering channel device (Tapchan) raising incoming waves into a lagoon on a Norwegian island and an OWC device on the same island. The Norwegian devices are delivering electricity at about 5.5p/KWh and 4p/KWh respectively with possibilities for reduction to 2.5-3p/KWh and 3p/KWh under favourable circumstances. The discussion ranged over comparisons with progress in wind power, engineering aspects, differences between inshore and offshore devices, tidal range and energy storage. (UK).

Tunnel effect wave energy detection

Science.gov (United States)

Kaiser, William J. (Inventor); Waltman, Steven B. (Inventor); Kenny, Thomas W. (Inventor)

1995-01-01

Methods and apparatus for measuring gravitational and inertial forces, magnetic fields, or wave or radiant energy acting on an object or fluid in space provide an electric tunneling current through a gap between an electrode and that object or fluid in space and vary that gap with any selected one of such forces, magnetic fields, or wave or radiant energy acting on that object or fluid. These methods and apparatus sense a corresponding variation in an electric property of that gap and determine the latter force, magnetic fields, or wave or radiant energy in response to that corresponding variation, and thereby sense or measure such parameters as acceleration, position, particle mass, velocity, magnetic field strength, presence or direction, or wave or radiant energy intensity, presence or direction.

Prototype Testing of the Wave Energy Converter Wave Dragon

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter; Friis-Madsen, Erik

2006-01-01

The Wave Dragon is an offshore wave energy converter of the overtopping type. It consists of two wave reflectors focusing the incoming waves towards a ramp, a reservoir for collecting the overtopping water and a number of hydro turbines for converting the pressure head into power. In the period...... from 1998 to 2001 extensive wave tank testing on a scale model was carried at Aalborg University. Then, a 57!27 m wide and 237 tonnes heavy (incl. ballast) prototype of the Wave Dragon, placed in Nissum Bredning, Denmark, was grid connected in May 2003 as the world’s first offshore wave energy...... converter. The prototype is fully equipped with hydro turbines and automatic control systems, and is instrumented in order to monitor power production, wave climate, forces in mooring lines, stresses in the structure and movements of the Wave Dragon. In the period May 2003 to January 2005 an extensive...

Prototype Testing of the Wave Energy Converter Wave Dragon

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter Bak; Friis-Madsen, Erik

2004-01-01

The Wave Dragon is an offshore wave energy converter of the overtopping type. It consists of two wave reflectors focusing the incoming waves towards a ramp, a reservoir for collecting the overtopping water and a number of hydro turbines for converting the pressure head into power. In the period...... from 1998 to 2001 extensive wave tank testing on a scale model was carried at Aalborg University. Then, a 57 x 27 m wide and 237 tonnes heavy (incl. ballast) prototype of the Wave Dragon, placed in Nissum Bredning, Denmark, was grid connected in May 2003 as the world's first offshore wave energy...... converter. The prototype is fully equipped with hydro turbines and automatic control systems, and is instrumented in order to monitor power production, wave climate, forces in mooring lines, stresses in the structure and movements of the Wave Dragon. During the last months, extensive testing has started...

Final Report Feasibility Study for the California Wave Energy Test Center (CalWavesm)

Energy Technology Data Exchange (ETDEWEB)

Blakeslee, Samuel Norman [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States). Inst. for Advanced Technology and Public Policy; Toman, William I. [Protean Wave Energy Ltd., Los Osos, CA (United States); Williams, Richard B. [Leidos Maritime Solutions, Reston, VA (United States); Davy, Douglas M. [CH2M, Sacramento, CA (United States); West, Anna [Kearns and West, Inc., San Francisco, CA (United States); Connet, Randy M. [Omega Power Engineers, LLC, Anaheim, CA (United States); Thompson, Janet [Kearns and West, Inc., San Francisco, CA (United States); Dolan, Dale [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States); Baltimore, Craig [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States); Jacobson, Paul [Electric Power Research Inst. (EPRI), Knoxville, TN (United States); Hagerman, George [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Potter, Chris [California Natural Resources Agency, Sacramento, CA (United States); Dooher, Brendan [Pacific Gas and Electric Company, San Francisco, CA (United States); Wendt, Dean [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States); Sheppard, Colin [Humboldt State Univ., Arcata, CA (United States); Harris, Andrew [Humboldt State Univ., Arcata, CA (United States); Lawson, W. Graham [Power Delivery Consultants, Inc., Albany, NY (United States)

2017-07-31

The California Wave Energy Test Center (CalWave) Feasibility Study project was funded over multiple phases by the Department of Energy to perform an interdisciplinary feasibility assessment to analyze the engineering, permitting, and stakeholder requirements to establish an open water, fully energetic, grid connected, wave energy test center off the coast of California for the purposes of advancing U.S. wave energy research, development, and testing capabilities. Work under this grant included wave energy resource characterization, grid impact and interconnection requirements, port infrastructure and maritime industry capability/suitability to accommodate the industry at research, demonstration and commercial scale, and macro and micro siting considerations. CalWave Phase I performed a macro-siting and down-selection process focusing on two potential test sites in California: Humboldt Bay and Vandenberg Air Force Base. This work resulted in the Vandenberg Air Force Base site being chosen as the most favorable site based on a peer reviewed criteria matrix. CalWave Phase II focused on four siting location alternatives along the Vandenberg Air Force Base coastline and culminated with a final siting down-selection. Key outcomes from this work include completion of preliminary engineering and systems integration work, a robust turnkey cost estimate, shoreside and subsea hazards assessment, storm wave analysis, lessons learned reports from several maritime disciplines, test center benchmarking as compared to existing international test sites, analysis of existing applicable environmental literature, the completion of a preliminary regulatory, permitting and licensing roadmap, robust interaction and engagement with state and federal regulatory agency personnel and local stakeholders, and the population of a Draft Federal Energy Regulatory Commission (FERC) Preliminary Application Document (PAD). Analysis of existing offshore oil and gas infrastructure was also performed

Investigation of Wave Transmission from a Floating Wave Dragon Wave Energy Converter

DEFF Research Database (Denmark)

Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

2012-01-01

This paper focuses on the calibration of the MIKE21BW model against the measured wave height reduction behind a 24 kW/m Wave Dragon (WD) wave energy converter. A numerical model is used to determine the wave transmission through the floating WD in varying wave conditions. The transmission obtained...

Floating attenuator wave energy device: Wavegen HYDRA project

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-07-01

This report describes research funded by the Department of Trade and Industry (DTI) into the feasibility of developing and constructing a floating attenuator wave energy device known as HYDRA following initial studies by Wavegen. HYDRA is a floating externally tensioned articulated raft wave energy generator based on work by Professor FJM Farley and colleagues during the 1980s. The project's first four work tasks confirmed the theoretical potential of the device but also highlighted significant practical problems in translating that potential into a viable design. It was therefore decided not to proceed further, i.e. not to construct and test a prototype device. The report provides a general description of the device and describes the results of the initial analysis and the first series of model tests. It then discusses device design and component testing and explains the methodology for determining device performance at a particular site and mathematical modelling of a one-third scale device. To help future research and development programmes, the report emphasises the generic problems associated with the development of wave devices.

Energy balance of plasma with wave taking the nonpotential nature of the waves into consideration

International Nuclear Information System (INIS)

Gel'berg, M.G.; Volosevich, A.V.

1986-01-01

It is shown that in the ionospheric plasma the potential electric field of low-frequency plasma waves is shifted in phase with respect to fluctuations of current by approximately -π/2 and the rotational field is almost in phase with the current. Therefore, the energy transfer between the plasma and the wave occurs mainly with the participation of rotational field

Ocean wave energy conversion

CERN Document Server

McCormick, Michael E

2007-01-01

This volume will prove of vital interest to those studying the use of renewable resources. Scientists, engineers, and inventors will find it a valuable review of ocean wave mechanics as well as an introduction to wave energy conversion. It presents physical and mathematical descriptions of the nine generic wave energy conversion techniques, along with their uses and performance characteristics.Author Michael E. McCormick is the Corbin A. McNeill Professor of Naval Engineering at the U.S. Naval Academy. In addition to his timely and significant coverage of possible environmental effects associa

Transmission of wave energy through an offshore wind turbine farm

DEFF Research Database (Denmark)

Christensen, Erik Damgaard; Johnson, Martin; Sørensen, Ole Rene

2013-01-01

condition at infinity. From airborne and Satellite SAR (Synthetic Aperture Radar) a model has been derived for the change of the water surface friction C) inside and on the lee side of the offshore wind farm. The effects have been implemented in a spectral wind wave model,MIKE21 SW, and a parametric study......The transmission of wave energy passing an offshore wind farm is studied. Three effects that can change the wave field are analysed, which is the A) energy dissipation due to drag resistance, B) wave reflection/diffraction from structures, and C) the effect of a modified wind field inside...... and on the lee side of the wind farm. The drag dissipation, A), is quantified by a quadratic resistance law. The effect of B) is parameterised based on 1st order potential theory. A method to find the amount of reflected and transmitted wave energy is developed based on the panel method WAMIT™ and a radiation...

Wave Induced Loads on the LEANCON Wave Energy Converter

DEFF Research Database (Denmark)

Frigaard, Peter; Kofoed, Jens Peter; Beserra, Eliab Ricarte

This report is a product of the co-operation agreement between Aalborg University and LEANCON (by Kurt Due Rasmussen) on the evaluation and development of the LEANCON wave energy converter (WEC). The work reported here has focused on evaluation of the wave induced loads on the device, based...... in the laboratory, all under the supervision of the personnel of the Wave Energy Research Group at Department of Civil Engineering, Aalborg University....

Testing, Analysis and Control of Wave Dragon, Wave Energy Converter

DEFF Research Database (Denmark)

Tedd, James

of the incident waves upon a wave device allows the possibility of accurately tuning the power-take off mechanism (the hydro-turbines for the Wave Dragon) to capture more energy. A digital filter method for performing this prediction in real-time with minimal computational effort is presented. Construction...... of digital filters is well known within signal processing, but their use for this application in Wave Energy is new. The filter must be designed carefully as the frequency components of waves travel at different speeds. Research presented in this thesis has advanced the development of the Wave Dragon device...

Microscopic optical potential at medium energies

International Nuclear Information System (INIS)

Malecki, A.

1979-01-01

The problems concerning a microscopic optical model for the elastic nuclear collisions at medium energies are discussed. We describe the method for constructing the optical potential which makes use of the particular properties of quantum scattering in the eikonal limit. The resulting potential is expressed in terms of the nuclear wave functions and the nucleon-nucleon scattering amplitudes. This potential has a dynamic character since by including the effects of multiple scattering it allows for the possibility of intermediate excitations of the projectile and target nuclei. The use of the potential in the exact wave equation accounts for the most important mechanisms present in the collisions between composite particles. The microscopic optical model was successfully applied in the analysis of elastic scattering of protons and α-particles on atomic nuclei in the energy range of 300-1000 MeV/nucleon. The dynamic optical potential in this case represents a considerable improvement over the eikonal Glauber model and the static optical potential of Watson. The possibilities to extend the microscopic description of the proton-nucleus interaction by considering the spin dependence of the elementary amplitude and the Majorana exchange effects were investigated. (author)

Enhancing Wave Energy Competitiveness through Co-Located Wind and Wave Energy Farms. A Review on the Shadow Effect

Directory of Open Access Journals (Sweden)

Sharay Astariz

2015-07-01

Full Text Available Wave energy is one of the most promising alternatives to fossil fuels due to the enormous available resource; however, its development may be slowed as it is often regarded as uneconomical. The largest cost reductions are expected to be obtained through economies of scale and technological progress. In this sense, the incorporation of wave energy systems into offshore wind energy farms is an opportunity to foster the development of wave energy. The synergies between both renewables can be realised through these co-located energy farms and, thus, some challenges of offshore wind energy can be met. Among them, this paper focuses on the longer non-operational periods of offshore wind turbines—relative to their onshore counterparts—typically caused by delays in maintenance due to the harsh marine conditions. Co-located wave energy converters would act as a barrier extracting energy from the waves and resulting in a shielding effect over the wind farm. On this basis, the aim of this paper is to analyse wave energy economics in a holistic way, as well as the synergies between wave and offshore wind energy, focusing on the shadow effect and the associated increase in the accessibility to the wind turbines.

Problems of application of wave energy

International Nuclear Information System (INIS)

D'yakov, A.F.; Morozkina, M.V.

1993-01-01

Technical solutions of using the energy both sea waves and lake ones are analyzed. Mathematical description of wave processes and phenomena as well as techniques of selection and conversion of the wave energy are given. Wave energy electromechanical converters are considered. Great attention is paid to linear generators of electromechanical converters eddy currents in massive sections of these generators and features of their calculation. Techniques for optimization of the linear generator parameters are shown. 60 refs

Hydraulic Response of the Wave Energy Converter Wave Dragon in Nissum Bredning

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter

This report deals with the hydraulic performance of the wave energy converter Wave Dragon, Nissum Bredning prototype.......This report deals with the hydraulic performance of the wave energy converter Wave Dragon, Nissum Bredning prototype....

The Crest Wing Wave Energy Device

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Antonishen, Michael Patrick

to generate power. Model tests have been performed using scale models (length scale 1:30), provided by WaveEnergyFyn, in regular and irregular wave states that can be found in Assessment of Wave Energy Devices. Best Practice as used in Denmark (Frigaard et al., 2008). The tests were carried out at Dept....... of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The displacement and force applied to a power take off system, provided by WaveEnergyFyn, were measured and used to calculate mechanical power available to the power take off....

Gravitational Waves and Dark Energy

Directory of Open Access Journals (Sweden)

Peter L. Biermann

2014-12-01

Full Text Available The idea that dark energy is gravitational waves may explain its strength and its time-evolution. A possible concept is that dark energy is the ensemble of coherent bursts (solitons of gravitational waves originally produced when the first generation of super-massive black holes was formed. These solitons get their initial energy as well as keep up their energy density throughout the evolution of the universe by stimulating emission from a background, a process which we model by working out this energy transfer in a Boltzmann equation approach. New Planck data suggest that dark energy has increased in strength over cosmic time, supporting the concept here. The transit of these gravitational wave solitons may be detectable. Key tests include pulsar timing, clock jitter and the radio background.

Ocean Wave Energy: Underwater Substation System for Wave Energy Converters

International Nuclear Information System (INIS)

Rahm, Magnus

2010-01-01

This thesis deals with a system for operation of directly driven offshore wave energy converters. The work that has been carried out includes laboratory testing of a permanent magnet linear generator, wave energy converter mechanical design and offshore testing, and finally design, implementation, and offshore testing of an underwater collector substation. Long-term testing of a single point absorber, which was installed in March 2006, has been performed in real ocean waves in linear and in non-linear damping mode. The two different damping modes were realized by, first, a resistive load, and second, a rectifier with voltage smoothing capacitors and a resistive load in the DC-link. The loads are placed on land about 2 km east of the Lysekil wave energy research site, where the offshore experiments have been conducted. In the spring of 2009, another two wave energy converter prototypes were installed. Records of array operation were taken with two and three devices in the array. With two units, non-linear damping was used, and with three units, linear damping was employed. The point absorbers in the array are connected to the underwater substation, which is based on a 3 m3 pressure vessel standing on the seabed. In the substation, rectification of the frequency and amplitude modulated voltages from the linear generators is made. The DC voltage is smoothened by capacitors and inverted to 50 Hz electrical frequency, transformed and finally transmitted to the on-shore measuring station. Results show that the absorption is heavily dependent on the damping. It has also been shown that by increasing the damping, the standard deviation of electrical power can be reduced. The standard deviation of electrical power is reduced by array operation compared to single unit operation. Ongoing and future work include the construction and installation of a second underwater substation, which will connect the first substation and seven new WECs

Modeling of MeV alpha particle energy transfer to lower hybrid waves

International Nuclear Information System (INIS)

Schivell, J.; Monticello, D.A.; Fisch, N.; Rax, J.M.

1993-10-01

The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. An initial analytic study was done by Fisch and Rax. Here the authors calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favorable for wave amplification from alpha energy. They find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the energy transfer, is investigated. This technique is shown to offer a large potential benefit

Benefits of up-wave measurements in linear short-term wave forecasting for wave energy applications

OpenAIRE

Paparella, Francesco; Monk, Kieran; Winands, Victor; Lopes, Miguel; Conley, Daniel; Ringwood, John

2014-01-01

The real-time control of wave energy converters requires the prediction of the wave elevation at the location of the device in order to maximize the power extracted from the waves. One possibility is to predict the future wave elevation by combining its past history with the spatial information coming from a sensor which measures the free surface elevation upwave of the wave energy converter. As an application example, the paper focuses on the prediction of the wave eleva...

Harnessing the Ocean's Power : Energy from Waves and Currents (Part I)

OpenAIRE

Yukihisa, Washio; Japan Marine Science and Technology Center

1985-01-01

The oceans are a potential source of renewable and pollution-free energy of particular importance to Japan. In this Issue we look at current development work to harness wave energy for power generation.

An oscillating wave energy converter with nonlinear snap-through Power-Take-Off systems in regular waves

Science.gov (United States)

Zhang, Xian-tao; Yang, Jian-min; Xiao, Long-fei

2016-07-01

Floating oscillating bodies constitute a large class of wave energy converters, especially for offshore deployment. Usually the Power-Take-Off (PTO) system is a directly linear electric generator or a hydraulic motor that drives an electric generator. The PTO system is simplified as a linear spring and a linear damper. However the conversion is less powerful with wave periods off resonance. Thus, a nonlinear snap-through mechanism with two symmetrically oblique springs and a linear damper is applied in the PTO system. The nonlinear snap-through mechanism is characteristics of negative stiffness and double-well potential. An important nonlinear parameter γ is defined as the ratio of half of the horizontal distance between the two springs to the original length of both springs. Time domain method is applied to the dynamics of wave energy converter in regular waves. And the state space model is used to replace the convolution terms in the time domain equation. The results show that the energy harvested by the nonlinear PTO system is larger than that by linear system for low frequency input. While the power captured by nonlinear converters is slightly smaller than that by linear converters for high frequency input. The wave amplitude, damping coefficient of PTO systems and the nonlinear parameter γ affect power capture performance of nonlinear converters. The oscillation of nonlinear wave energy converters may be local or periodically inter well for certain values of the incident wave frequency and the nonlinear parameter γ, which is different from linear converters characteristics of sinusoidal response in regular waves.

Worlds Largest Wave Energy Project 2007 in Wales

DEFF Research Database (Denmark)

Christensen, Lars; Friis-Madsen, Erik; Kofoed, Jens Peter

2006-01-01

This paper introduces world largest wave energy project being developed in Wales and based on one of the leading wave energy technologies. The background for the development of wave energy, the total resource ands its distribution around the world is described. In contrast to wind energy turbines...... Dragon has to be scaled in accordance with the wave climate at the deployment site, which makes the Welch demonstrator device the worlds largest WEC so far with a total width of 300 meters. The project budget, the construction methods and the deployment site are also given....... a large number of fundamentally different technologies are utilised to harvest wave energy. The Wave Dragon belongs to the wave overtopping class of converters and the paper describes the fundamentals and the technical solutions used in this wave energy converter. An offshore floating WEC like the Wave...

Comparative analysis of winch-based wave energy converters

OpenAIRE

Nachev, Aleksandar

2017-01-01

Renewable energy sources are probably the future of the mankind. The main points advocating wave energy in particular include its huge potential, low environmental impact and availability around the globe. In order to harvest that energy, however, engineers have to overcome, among others, the corrosive sea environment and the unpredictable storms as well as secure funding for research and development. A lot of effort has been put into building and testing WECs after the oil crisis in the 1970...

Performance Evaluation of Wave Energy Converters

DEFF Research Database (Denmark)

Pecher, Arthur

Ocean waves provide a sustainable, power-dense, predictable and widely available source of energy that could provide about 10 % of worlds energy needs. While research into waveenergy has been undertaken for decades, a significant increase in related activities has been seen in the recent years......, with more than 150 concepts currently being developed worldwide. Wave energy conversion concepts can be of many kinds, as the energy in the waves can be absorbed in many different ways. However, each concept is expected to require a thorough development process, involving different phases and prototypes....... Guidelines for the development of wave energy converters recommend the use of different prototypes, having different sizes, which have to perform tank tests or sea trials. Thisimplicates the need of different testing environment, which shifts from being controllable to uncontrollable with the development...

Innovative Basis of Research of Energy-Efficient Potential and Effectiveness of Renewable Energy Sources

OpenAIRE

Hasanov Seymur Latif oglu; Hasanov Elnur Latif oglu

2018-01-01

In recent years, countries of the world have been trying to attract new energy sources (wind, sun, biogas, waves, drainage, non-conventional energy sources such as hydroelectric power of small rivers) in their fuel-energy balance. Azerbaijan has renewable natural resources, favorable for its energy-efficient potential, according to the amount of sunny and windy days. In this article was given total information about renewable energy potential of Azerbaijan Republic. In this article we use inf...

Energy conversion of orbital motions in gravitational waves: Simulation and test of the Seaspoon wave energy converter

International Nuclear Information System (INIS)

Di Fresco, L.; Traverso, A.

2014-01-01

Highlights: • We investigate an innovative wave energy converter. • We study a robust technology derived from wind power sector. • We increased the performance of a drag type rotor exploiting the motion of ocean waves and a simple flat plate component. • We proved the working principle with a numerical model first and with experimental test in wave flume later. • We aim to obtain a robust large energy harvester able to operate in mild energy sea and with an extended operating range. - Abstract: The conversion of ocean wave power into sustainable electrical power represents a major opportunity to Nations endowed with such a kind of resource. At the present time the most of the technological innovations aiming at converting such resources are at early stage of development, with only a handful of devices close to be at the commercial demonstration stage. The Seaspoon device, thought as a large energy harvester, catches the kinetic energy of ocean waves with promising conversion efficiency, and robust technology, according to specific “wave-motion climate”. University of Genoa aims to develop a prototype to be deployed in medium average energy content seas (i.e. Mediterranean or Eastern Asia seas). This paper presents the first simulation and experimental results carried out on a reduced scale proof-of-concept model tested in the laboratory wave flume

On the dynamics of a novel ocean wave energy converter

KAUST Repository

Orazov, B.

2010-11-01

Buoy-type ocean wave energy converters are designed to exhibit resonant responses when subject to excitation by ocean waves. A novel excitation scheme is proposed which has the potential to improve the energy harvesting capabilities of these converters. The scheme uses the incident waves to modulate the mass of the device in a manner which amplifies its resonant response. To illustrate the novel excitation scheme, a simple one-degree of freedom model is developed for the wave energy converter. This model has the form of a switched linear system. After the stability regime of this system has been established, the model is then used to show that the excitation scheme improves the power harvesting capabilities by 2565 percent even when amplitude restrictions are present. It is also demonstrated that the sensitivity of the device\\'s power harvesting capabilities to changes in damping becomes much smaller when the novel excitation scheme is used. © 2010 Elsevier Ltd. All rights reserved.

Small amplitude transverse waves on taut strings: exploring the significant effects of longitudinal motion on wave energy location and propagation

International Nuclear Information System (INIS)

Rowland, David R

2013-01-01

Introductory discussions of energy transport due to transverse waves on taut strings universally assume that the effects of longitudinal motion can be neglected, but this assumption is not even approximately valid unless the string is idealized to have a zero relaxed length, a requirement approximately met by the slinky spring. While making this additional idealization is probably the best approach to take when discussing waves on strings at the introductory level, for intermediate to advanced undergraduate classes in continuum mechanics and general wave phenomena where somewhat more realistic models of strings can be investigated, this paper makes the following contributions. First, various approaches to deriving the general energy continuity equation are critiqued and it is argued that the standard continuum mechanics approach to deriving such equations is the best because it leads to a conceptually clear, relatively simple derivation which provides a unique answer of greatest generality. In addition, a straightforward algorithm for calculating the transverse and longitudinal waves generated when a string is driven at one end is presented and used to investigate a cos 2 transverse pulse. This example illustrates much important physics regarding energy transport in strings and allows the ‘attack waves’ observed when strings in musical instruments are struck or plucked to be approximately modelled and analysed algebraically. Regarding the ongoing debate as to whether the potential energy density in a string can be uniquely defined, it is shown by coupling an external energy source to a string that a suggested alternative formula for potential energy density requires an unphysical potential energy to be ascribed to the source for overall energy to be conserved and so cannot be considered to be physically valid. (paper)

Marine Hydrokinetic Energy Site Identification and Ranking Methodology Part I: Wave Energy

Energy Technology Data Exchange (ETDEWEB)

Kilcher, Levi [National Renewable Energy Lab. (NREL), Golden, CO (United States); Thresher, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-10-01

, Hawaii and the Pacific Northwest (northern California, Oregon, and Washington) rank at the top of the lists. Hawaii ranks highest in the near-term scenario because it has high energy costs. In the long-term scenario, Oregon ranks highest because it has a large market and an energetic resource. Several East Coast states and Puerto Rico are also identified as potential wave energy deployment sites if technological innovations make it possible to efficiently generate electricity from the modest resource there. There are also several small-market sites in Alaska and U.S. Pacific Islands that rank particularly well in the near-term analysis due to their high energy prices. These locations may represent opportunities to demonstrate economical wave energy conversion as a stepping-stone to larger markets. Several factors that will affect wave project costs and siting have not been considered here -- including permitting constraints, conflicting use, seasonal resource variability, extreme event likelihood, and distance to ports -- because consistent data are unavailable or technology-independent scoring could not be identified. As the industry continues to mature and converge around a subset of device archetypes with well-defined costs, more precise investigations of project siting that include these factors will be possible. For now, these results provide a high-level guide pointing to the regions where markets and resource will one day support commercial wave energy projects.

Handbook of ocean wave energy

CERN Document Server

Kofoed, Jens

2017-01-01

This book is open access under a CC BY-NC 2.5 license. This book offers a concise, practice-oriented reference-guide to the field of ocean wave energy. The ten chapters highlight the key rules of thumb, address all the main technical engineering aspects and describe in detail all the key aspects to be considered in the techno-economic assessment of wave energy converters. Written in an easy-to-understand style, the book answers questions relevant to readers of different backgrounds, from developers, private and public investors, to students and researchers. It is thereby a valuable resource for both newcomers and experienced practitioners in the wave energy sector.

Investigation on the possibility of extracting wave energy from the Texas coast

Science.gov (United States)

Haces-Fernandez, Francisco

Due to the great and growing demand of energy consumption in the Texas Coast area, the generation of electricity from ocean waves is considered very important. The combination of the wave energy with offshore wind power is explored as a way to increase power output, obtain synergies, maximize the utilization of assigned marine zones and reduce variability. Previously literature has assessed the wave energy generation, combined with wind in different geographic locations such as California, Ireland and the Azores Island. In this research project, the electric power generation from ocean waves on the Texas Coast was investigated, assessing its potential from the meteorological data provided by five buoys from National Data Buoy Center of the National Oceanic and Atmospheric Administration, considering the Pelamis 750 kW Wave Energy Converter (WEC) and the Vesta V90 3 MW Wind Turbine. The power output from wave energy was calculated for the year 2006 using Matlab, and the results in several locations were considered acceptable in terms of total power output, but with a high temporal variability. To reduce its variability, wave energy was combined with wind energy, obtaining a significant reduction on the coefficient of variation on the power output. A Matlab based interface was created to calculate power output and its variability considering data from longer periods of time.

Renewable energy potential in Southern Africa: conference proceedings

International Nuclear Information System (INIS)

1986-01-01

This conference, held in Cape Town from 8-10 September 1986, consist of many papers discussing the renewalble energy potential in Southern Africa. The papers delivered at the conference include topics such as wind energy, ocean energy, hydroelectric resources, solar resources, wave energy, agroforestry, fuelwood, hydrogen energy and the production of energy from biomass. Several papers were delivered on solar water heating and one on nuclear vs renewable energy

Design Specifications for the Hanstholm WEPTOS Wave Energy Converter

DEFF Research Database (Denmark)

Pecher, Arthur; Kofoed, Jens Peter; Larsen, Tommy

2012-01-01

The WEPTOS wave energy converter (WEC) is a novel device that combines an established and efficient wave energy absorbing mechanism with a smart structure, which can regulate the amount of incoming wave energy and reduce loads in extreme wave conditions. This adjustable A-shaped slack-moored and ......The WEPTOS wave energy converter (WEC) is a novel device that combines an established and efficient wave energy absorbing mechanism with a smart structure, which can regulate the amount of incoming wave energy and reduce loads in extreme wave conditions. This adjustable A-shaped slack...

Wave-current interactions at the FloWave Ocean Energy Research Facility

Science.gov (United States)

Noble, Donald; Davey, Thomas; Steynor, Jeffrey; Bruce, Tom; Smith, Helen; Kaklis, Panagiotis

2015-04-01

Physical scale model testing is an important part of the marine renewable energy development process, allowing the study of forces and device behaviour in a controlled environment prior to deployment at sea. FloWave is a new state-of-the-art ocean energy research facility, designed to provide large scale physical modelling services to the tidal and wave sector. It has the unique ability to provide complex multi-directional waves that can be combined with currents from any direction in the 25m diameter circular tank. The facility is optimised for waves around 2s period and 0.4m height, and is capable of generating currents upwards of 1.6m/s. This offers the ability to model metocean conditions suitable for most renewable energy devices at a typical scale of between 1:10 and 1:40. The test section is 2m deep, which can be classed as intermediate-depth for most waves of interest, thus the full dispersion equation must be solved as the asymptotic simplifications do not apply. The interaction between waves and currents has been studied in the tank. This has involved producing in the tank sets of regular waves, focussed wave groups, and random sea spectra including multi-directional sea states. These waves have been both inline-with and opposing the current, as well as investigating waves at arbitrary angles to the current. Changes in wave height and wavelength have been measured, and compared with theoretical results. Using theoretical wave-current interaction models, methods have been explored to "correct" the wave height in the central test area of the tank when combined with a steady current. This allows the wave height with current to be set equal to that without a current. Thus permitting, for example, direct comparison of device motion response between tests with and without current. Alternatively, this would also permit a specific wave height and current combination to be produced in the tank, reproducing recorded conditions at a particular site of interest. The

Energy dissipation through wind-generated breaking waves

Institute of Scientific and Technical Information of China (English)

ZHANG Shuwen; CAO Ruixue; XIE Lingling

2012-01-01

Wave breaking is an important process that controls turbulence properties and fluxes of heat and mass in the upper oceanic layer.A model is described for energy dissipation per unit area at the ocean surface attributed to wind-generated breaking waves,in terms of ratio of energy dissipation to energy input,windgenerated wave spectrum,and wave growth rate.Also advanced is a vertical distribution model of turbulent kinetic energy,based on an exponential distribution method.The result shows that energy dissipation rate depends heavily on wind speed and sea state.Our results agree well with predictions of previous works.

A wave model test bed study for wave energy resource characterization

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhaoqing; Neary, Vincent S.; Wang, Taiping; Gunawan, Budi; Dallman, Annie R.; Wu, Wei-Cheng

2017-12-01

This paper presents a test bed study conducted to evaluate best practices in wave modeling to characterize energy resources. The model test bed off the central Oregon Coast was selected because of the high wave energy and available measured data at the site. Two third-generation spectral wave models, SWAN and WWIII, were evaluated. A four-level nested-grid approach—from global to test bed scale—was employed. Model skills were assessed using a set of model performance metrics based on comparing six simulated wave resource parameters to observations from a wave buoy inside the test bed. Both WWIII and SWAN performed well at the test bed site and exhibited similar modeling skills. The ST4 package with WWIII, which represents better physics for wave growth and dissipation, out-performed ST2 physics and improved wave power density and significant wave height predictions. However, ST4 physics tended to overpredict the wave energy period. The newly developed ST6 physics did not improve the overall model skill for predicting the six wave resource parameters. Sensitivity analysis using different wave frequencies and direction resolutions indicated the model results were not sensitive to spectral resolutions at the test bed site, likely due to the absence of complex bathymetric and geometric features.

Conservation laws of wave action and potential enstrophy for Rossby waves in a stratified atmosphere

Science.gov (United States)

Straus, D. M.

1983-01-01

The evolution of wave energy, enstrophy, and wave motion for atmospheric Rossby waves in a variable mean flow are discussed from a theoretical and pedagogic standpoint. In the absence of mean flow gradients, the wave energy density satisfies a local conservation law, with the appropriate flow velocity being the group velocity. In the presence of mean flow variations, wave energy is not conserved, but wave action is, provided the mean flow is independent of longitude. Wave enstrophy is conserved for arbitrary variations of the mean flow. Connections with Eliassen-Palm flux are also discussed.

Evaluation of the Wave Energy Conversion Efficiency in Various Coastal Environments

Directory of Open Access Journals (Sweden)

Eugen Rusu

2014-06-01

Full Text Available The main objective of the present work was to assess and compare the wave power resources in various offshore and nearshore areas. From this perspective, three different groups of coastal environments were considered: the western Iberian nearshore, islands and an enclosed environment with sea waves, respectively. Some of the most representative existent wave converters were evaluated in the analysis and a second objective was to compare their performances at the considered locations, and in this way to determine which is better suited for potential commercial exploitation. In order to estimate the electric power production expected in a certain location, the bivariate distributions of the occurrences corresponding to the sea states, defined by the significant wave height and the energy period, were constructed in each coastal area. The wave data were provided by hindcast studies performed with numerical wave models or based on measurements. The transformation efficiency of the wave energy into electricity is evaluated via the load factor and also through the capture width, defined as the ratio between the electric power estimated to be produced by each specific wave energy converters (WEC and the expected wave power corresponding to the location considered. Finally, by evaluating these two different indicators, comparisons of the performances of three WEC types (Aqua Buoy, Pelamis and Wave Dragon in the three different groups of coastal environments considered have been also carried out. The work provides valuable information related to the effectiveness of various technologies for the wave energy extraction that would operate in different coastal environments.

A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester

International Nuclear Information System (INIS)

Yoon, Sunghyun; Cho, Young-Ho

2014-01-01

We present a flexible piezoelectric generator, capable to harvest energy from human arterial pulse wave on the human wrist. Special features and advantages of the flexible piezoelectric generator include the multi-layer device design with contact windows and the simple fabrication process for the higher flexibility with the better energy harvesting efficiency. We have demonstrated the design effectiveness and the process simplicity of our skin- attachable flexible piezoelectric pulse wave energy harvester, composed of the sensitive P(VDF-TrFE) piezoelectric layer on the flexible polyimide support layer with windows. We experimentally characterize and demonstrate the energy harvesting capability of 0.2∼1.0μW in the Human heart rate range on the skin contact area of 3.71cm 2 . Additional physiological and/or vital signal monitoring devices can be fabricated and integrated on the skin attachable flexible generator, covered by an insulation layer; thus demonstrating the potentials and advantages of the present device for such applications to the flexible multi-functional selfpowered artificial skins, capable to detect physiological and/or vital signals on Human skin using the energy harvested from arterial pulse waves

Single-wave-number representation of nonlinear energy spectrum in elastic-wave turbulence of the Föppl-von Kármán equation: energy decomposition analysis and energy budget.

Science.gov (United States)

Yokoyama, Naoto; Takaoka, Masanori

2014-12-01

A single-wave-number representation of a nonlinear energy spectrum, i.e., a stretching-energy spectrum, is found in elastic-wave turbulence governed by the Föppl-von Kármán (FvK) equation. The representation enables energy decomposition analysis in the wave-number space and analytical expressions of detailed energy budgets in the nonlinear interactions. We numerically solved the FvK equation and observed the following facts. Kinetic energy and bending energy are comparable with each other at large wave numbers as the weak turbulence theory suggests. On the other hand, stretching energy is larger than the bending energy at small wave numbers, i.e., the nonlinearity is relatively strong. The strong correlation between a mode a(k) and its companion mode a(-k) is observed at the small wave numbers. The energy is input into the wave field through stretching-energy transfer at the small wave numbers, and dissipated through the quartic part of kinetic-energy transfer at the large wave numbers. Total-energy flux consistent with energy conservation is calculated directly by using the analytical expression of the total-energy transfer, and the forward energy cascade is observed clearly.

Enhancing Wave Energy Competitiveness through Co-Located Wind and Wave Energy Farms. A Review on the Shadow Effect

OpenAIRE

Sharay Astariz; Gregorio Iglesias

2015-01-01

Wave energy is one of the most promising alternatives to fossil fuels due to the enormous available resource; however, its development may be slowed as it is often regarded as uneconomical. The largest cost reductions are expected to be obtained through economies of scale and technological progress. In this sense, the incorporation of wave energy systems into offshore wind energy farms is an opportunity to foster the development of wave energy. The synergies between both renewables can be rea...

Teaching on ocean-wave-energy conversion

Energy Technology Data Exchange (ETDEWEB)

Falnes, J. [Norges teknisk-naturvitskaplege univ., Inst. for fysikk, Trondheim (Norway)

2001-07-01

Ocean-wave energy utilisation has for 27 years been a university research subject, in which the author has been active from the first year. In this paper he presents some information related to his teaching on the subject during many of these years. This includes teaching on the pre-university level and, in particular, development of the wave-energy module for an educational CD-ROM on sustainable technology and renewable energy. Education of the general public is very important. On the other hand teaching of doctor students and other wave-energy researchers is also a subject of the paper. (au)

Experimental Study on the WavePiston Wave Energy Converter

DEFF Research Database (Denmark)

Pecher, Arthur; Kofoed, Jens Peter; Angelelli, E.

This report presents the results of an experimental study of the power performance of the WavePiston wave energy converter. It focuses mainly on evaluating the power generating capabilities of the device and the effect of the following issues: Scaling ratios PTO loading Wave height and wave period...... dependency Oblique incoming waves Distance between plates During the study, the model supplied by the client, WavePiston, has been rigorously tested as all the anticipated tests have been done thoroughly and during all tests, good quality data has been obtained from all the sensors....

Wave-to-wire Modelling of Wave Energy Converters : Critical Assessment, Developments and Applicability for Economical Optimisation

DEFF Research Database (Denmark)

Ferri, Francesco

The idea to use the motion of a wavy sea surface to produce electricity was investigate in the seventies, in a time when the earliest wave energy converters were conceived and developed. But nowadays still none of the patented devices reached a commercial stage. Wave energy is a large, mostly...... untapped, renewable energy resource that has the potential to contribute significantly to the future energy mix, especially in an environmental friendly future scenario. What is bounding the sector to roll off into the market is the cost of the produced energy: too high if compared with other renewable...... energy sources. Generally speaking, the devices have a low efficiency and a high structural cost. The aim of the thesis is to push the research toward a cost minimisation algorithm, based on numerical simulation, which account for both efficiency and structural cost of the device. In order to achieve...

Reliability and Maintenance for Offshore Wind Turbines and Wave Energy Devices

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard

2015-01-01

Wind turbines are in some countries contributing significantly the production of electricity and wave energy devices have the potential to be developed in a similarway. For both offshore wind turbines and wave energy devices reliability is a key issue since costs to operation and maintenance may...... be significant contributors to the Levelized Cost Of Energy and OM costs are highly dependent on the reliability of the components implying that it is important to focus on increasing the reliability as much as is economically reasonable. This paper describes basic aspects for reliability analysis of wind...... turbines and wave energy devices with special focus on structural components. The reliability assessment needs include the effects of the control system and possible faults due to failure of electrical/mechanical components and e.g. loss of grid connection. The target reliability level for wind turbine...

Short-Term Wave Forecasting for Real-Time Control of Wave Energy Converters

OpenAIRE

Fusco, Francesco; Ringwood, John

2010-01-01

Real-time control of wave energy converters requires knowledge of future incident wave elevation in order to approach optimal efficiency of wave energy extraction. We present an approach where the wave elevation is treated as a time series and it is predicted only from its past history. A comparison of a range of forecasting methodologies on real wave observations from two different locations shows how the relatively simple linear autoregressive model, which implicitly models the cyclical beh...

Clustering of cycloidal wave energy converters

Science.gov (United States)

Siegel, Stefan G.

2016-03-29

A wave energy conversion system uses a pair of wave energy converters (WECs) on respective active mountings on a floating platform, so that the separation of the WECs from each other or from a central WEC can be actively adjusted according to the wavelength of incident waves. The adjustable separation facilitates operation of the system to cancel reactive forces, which may be generated during wave energy conversion. Modules on which such pairs of WECs are mounted can be assembled with one or more central WECs to form large clusters in which reactive forces and torques can be made to cancel. WECs of different sizes can be employed to facilitate cancelation of reactive forces and torques.

Controller for a wave energy converter

Science.gov (United States)

Wilson, David G.; Bull, Diana L.; Robinett, III, Rush D.

2015-09-22

A wave energy converter (WEC) is described, the WEC including a power take off (PTO) that converts relative motion of bodies of the WEC into electrical energy. A controller controls operation of the PTO, causing the PTO to act as a motor to widen a wave frequency spectrum that is usable to generate electrical energy.

Performance Evaluation of Wave Energy Converters

DEFF Research Database (Denmark)

Pecher, Arthur

. Guidelines for the development of wave energy converters recommend the use of different prototypes, having different sizes, which have to perform tank tests or sea trials. This implicates the need of different testing environment, which shifts from being controllable to uncontrollable with the development......, with more than 150 concepts currently being developed worldwide. Wave energy conversion concepts can be of many kinds, as the energy in the waves can be absorbed in many different ways. However, each concept is expected to require a thorough development process, involving different phases and prototypes...

Benchmark Modeling of the Near-Field and Far-Field Wave Effects of Wave Energy Arrays

Energy Technology Data Exchange (ETDEWEB)

Rhinefrank, Kenneth E; Haller, Merrick C; Ozkan-Haller, H Tuba

2013-01-26

This project is an industry-led partnership between Columbia Power Technologies and Oregon State University that will perform benchmark laboratory experiments and numerical modeling of the near-field and far-field impacts of wave scattering from an array of wave energy devices. These benchmark experimental observations will help to fill a gaping hole in our present knowledge of the near-field effects of multiple, floating wave energy converters and are a critical requirement for estimating the potential far-field environmental effects of wave energy arrays. The experiments will be performed at the Hinsdale Wave Research Laboratory (Oregon State University) and will utilize an array of newly developed Buoys' that are realistic, lab-scale floating power converters. The array of Buoys will be subjected to realistic, directional wave forcing (1:33 scale) that will approximate the expected conditions (waves and water depths) to be found off the Central Oregon Coast. Experimental observations will include comprehensive in-situ wave and current measurements as well as a suite of novel optical measurements. These new optical capabilities will include imaging of the 3D wave scattering using a binocular stereo camera system, as well as 3D device motion tracking using a newly acquired LED system. These observing systems will capture the 3D motion history of individual Buoys as well as resolve the 3D scattered wave field; thus resolving the constructive and destructive wave interference patterns produced by the array at high resolution. These data combined with the device motion tracking will provide necessary information for array design in order to balance array performance with the mitigation of far-field impacts. As a benchmark data set, these data will be an important resource for testing of models for wave/buoy interactions, buoy performance, and far-field effects on wave and current patterns due to the presence of arrays. Under the proposed project we will initiate

Hydrodynamic Investigation of a Concentric Cylindrical OWC Wave Energy Converter

Directory of Open Access Journals (Sweden)

Yu Zhou

2018-04-01

Full Text Available A fixed, concentric, cylindrical oscillating water column (OWC wave energy converter (WEC is proposed for shallow offshore sites. Compared with the existing shoreline OWC device, this wave energy device is not restricted by the wave directions and coastline geography conditions. Analytical solutions are derived based on the linear potential-flow theory and eigen-function expansion technique to investigate hydrodynamic properties of the device. Three typical free-surface oscillation modes in the chamber are discussed, of which the piston-type mode makes the main contribution to the energy conversion. The effects of the geometrical parameters on the hydrodynamic properties are further investigated. The resonance frequency of the chamber, the power extraction efficiency, and the effective frequency bandwidth of the device is discussed, amongst other topics. It is found that the proposed OWC-WEC device with a lower draft and wider chamber breadth has better power extraction ability.

Determination of the S-wave scattering shape parameter P from the zero-energy wave function

International Nuclear Information System (INIS)

Kermode, M.W.; van Dijk, W.

1990-01-01

We show that for S-wave scattering at an energy k 2 by a local potential which supports no more than one bound state, the shape parameter P and coefficients of higher powers of k 2 in the effective range expansion function cotδ=-1/a+1/2 r 0 k 2 -Pr 0 3 k 3 +Qr 0 5 k 6 +..., where δ is the phase shift, may be obtained from the zero-energy wave function, u 0 (r). Thus δ itself may be determined from u 0 . We show that Pr 0 3 =∫ 0 R [β(r)u 0 2 (r)-bar β(r)bar u 0 2 (r)]dr, where r 0 is the effective range, β(r) is determined from an integral involving the wave function, and bar β(r) is a simple function of r which involves the scattering length and effective range

Unusual energy properties of leaky backward Lamb waves in a submerged plate.

Science.gov (United States)

Nedospasov, I A; Mozhaev, V G; Kuznetsova, I E

2017-05-01

It is found that leaky backward Lamb waves, i.e. waves with negative energy-flux velocity, propagating in a plate submerged in a liquid possess extraordinary energy properties distinguishing them from any other type of waves in isotropic media. Namely, the total time-averaged energy flux along the waveguide axis is equal to zero for these waves due to opposite directions of the longitudinal energy fluxes in the adjacent media. This property gives rise to the fundamental question of how to define and calculate correctly the energy velocity in such an unusual case. The procedure of calculation based on incomplete integration of the energy flux density over the plate thickness alone is applied. The derivative of the angular frequency with respect to the wave vector, usually referred to as the group velocity, happens to be close to the energy velocity defined by this mean in that part of the frequency range where the backward mode exists in the free plate. The existence region of the backward mode is formally increased for the submerged plate in comparison to the free plate as a result of the liquid-induced hybridization of propagating and nonpropagating (evanescent) Lamb modes. It is shown that the Rayleigh's principle (i.e. equipartition of total time-averaged kinetic and potential energies for time-harmonic acoustic fields) is violated due to the leakage of Lamb waves, in spite of considering nondissipative media. Copyright © 2017 Elsevier B.V. All rights reserved.

Electromagnetic wave energy converter

Science.gov (United States)

Bailey, R. L. (Inventor)

1973-01-01

Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

Levelized Cost of Energy of the Weptos wave energy converter

DEFF Research Database (Denmark)

Pecher, Arthur; Kofoed, Jens Peter

This report presents the cost of energy calculations of a wave energy array of 90 MW, consisting of 25 x 3.6 MW Weptos wave energy converters. The calculation has been made in analogy with a publically available document presented by the UK government, covering the case of a similar size wind...

Characterisation of the biofouling community on a floating wave energy device.

Science.gov (United States)

Nall, Christopher R; Schläppy, Marie-Lise; Guerin, Andrew J

2017-05-01

Wave energy devices are novel structures in the marine environment and, as such, provide a unique habitat for biofouling organisms. In this study, destructive scrape samples and photoquadrats were used to characterise the temperate epibenthic community present on prototypes of the Pelamis wave energy converter. The biofouling observed was extensive and diverse with 115 taxa recorded including four non-native species. Vertical zonation was identified on the sides of the device, with an algae-dominated shallow subtidal area and a deeper area characterised by a high proportion of suspension-feeding invertebrates. Differences in species composition and biomass were also observed between devices, along the length of the device and between sampling dates. This research provides an insight into the variation of biofouling assemblages on a wave energy device as well as the potential technical and ecological implications associated with biofouling on marine renewable energy structures.

Predictability of Wave Energy and Electricity Markets

DEFF Research Database (Denmark)

Chozas, Julia Fernandez

2012-01-01

The articlw addresses an important challenge ahead the integration of the electricity generated by wave energy conversion technologies into the electric grid. Particularly, it looks into the role of wave energy within the day-ahead electricity market. For that the predictability of the theoretical...... power outputs of three wave energy technologies in the Danish North Sea are examined. The simultaneous and co-located forecast and buoy-measured wave parameters at Hanstholm, Denmark, during a non-consecutive autumn and winter 3-month period form the basis of the investigation. The objective...

Hydroelectromechanical modelling of a piezoelectric wave energy converter

Science.gov (United States)

Renzi, E.

2016-11-01

We investigate the hydroelectromechanical-coupled dynamics of a piezoelectric wave energy converter. The converter is made of a flexible bimorph plate, clamped at its ends and forced to motion by incident ocean surface waves. The piezoceramic layers are connected in series and transform the elastic motion of the plate into useful electricity by means of the piezoelectric effect. By using a distributed-parameter analytical approach, we couple the linear piezoelectric constitutive equations for the plate with the potential-flow equations for the surface water waves. The resulting system of governing partial differential equations yields a new hydroelectromechanical dispersion relation, whose complex roots are determined with a numerical approach. The effect of the piezoelectric coupling in the hydroelastic domain generates a system of short- and long-crested weakly damped progressive waves travelling along the plate. We show that the short-crested flexural wave component gives a dominant contribution to the generated power. We determine the hydroelectromechanical resonant periods of the device, at which the power output is significant.

Wave energy budget analysis in the Earth's radiation belts uncovers a missing energy.

Science.gov (United States)

Artemyev, A V; Agapitov, O V; Mourenas, D; Krasnoselskikh, V V; Mozer, F S

2015-05-15

Whistler-mode emissions are important electromagnetic waves pervasive in the Earth's magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and the upper-atmosphere ionization or chemical composition. Here, we report an analysis of 10-year Cluster data, statistically evaluating the full wave energy budget in the Earth's magnetosphere, revealing that a significant fraction of the energy corresponds to hitherto generally neglected very oblique waves. Such waves, with 10 times smaller magnetic power than parallel waves, typically have similar total energy. Moreover, they carry up to 80% of the wave energy involved in wave-particle resonant interactions. It implies that electron heating and precipitation into the atmosphere may have been significantly under/over-valued in past studies considering only conventional quasi-parallel waves. Very oblique waves may turn out to be a crucial agent of energy redistribution in the Earth's radiation belts, controlled by solar activity.

Electrical Systems for Wave Energy Conversion

Energy Technology Data Exchange (ETDEWEB)

Bostroem, Cecilia

2011-07-01

Wave energy is a renewable energy source with a large potential to contribute to the world's electricity production. There exist several technologies on how to convert the energy in the ocean waves into electric energy. The wave energy converter (WEC) presented in this thesis is based on a linear synchronous generator. The generator is placed on the seabed and driven by a point absorbing buoy on the ocean surface. Instead of having one large unit, several smaller units are interconnected to increase the total installed power. To convert and interconnect the power from the generators, marine substations are used. The marine substations are placed on the seabed and convert the fluctuating AC from the generators into an AC suitable for grid connection. The work presented in the thesis focuses on the first steps in the electric energy conversion, converting the voltage out from the generators into DC, which have an impact on the WEC's ability to absorb and produce power. The purpose has been to investigate how the generator will operate when it is subjected to different load cases and to obtain guidelines on how future systems could be improved. Offshore experiments and simulations have been done on full scale generators connected to four different loads, i.e. one linear resistive load and three different non-linear loads representing different cases for grid connected WECs. The results show that the power can be controlled and optimized by choosing a suitable system for the WEC. It is not obvious which kind of system is the most preferable, since there are many different parameters that have an impact on the system performance, such as the size of the buoy, how the generator is designed, the number of WECs, the highest allowed complexity of the system, costs and so on. Therefore, the design of the electrical system should preferably be carried out in parallel with the design of the WEC in order to achieve an efficient system

Tunneling and energy splitting in an asymmetric double-well potential

International Nuclear Information System (INIS)

Song, Dae-Yup

2008-01-01

An asymmetric double-well potential is considered, assuming that the minima of the wells are quadratic with a frequency ω and the difference of the minima is close to a multiple of hω. A WKB wave function is constructed on both sides of the local maximum between the wells, by matching the WKB function to the exact wave functions near the classical turning points. The continuities of the wave function and its first derivative at the local maximum then give the energy-level splitting formula, which not only reproduces the instanton result for a symmetric potential, but also elucidates the appearance of resonances of tunneling in the asymmetric potential

Fluctuation and thermal energy balance for drift-wave turbulence

International Nuclear Information System (INIS)

Kim, Chang-Bae; Horton, W.

1990-05-01

Energy conservation for the drift-wave system is shown to be separated into the wave-energy power balance equation and an ambient thermal-energy transport equation containing the anomalous transport fluxes produced by the fluctuations. The wave energy equation relates the wave energy density and wave energy flux to the anomalous transport flux and the dissipation of the fluctuations. The thermal balance equation determines the evolution of the temperature profiles from the divergence of the anomalous heat flux, the collisional heating and cooling mechanisms and the toroidal pumping effect. 16 refs., 1 tab

Fluctuation and thermal energy balance for drift-wave turbulence

International Nuclear Information System (INIS)

Changbae Kim; Horton, W.

1991-01-01

Energy conservation for the drift-wave system is shown to be separated into the wave-energy power balance equation and an ambient thermal-energy transport equation containing the anomalous transport fluxes produced by the fluctuations. The wave energy equation relates the wave energy density and wave energy flux to the anomalous transport flux and the dissipation of the fluctuations. The thermal balance equation determines the evolution of the temperature profiles from the divergence of the anomalous heat flux, the collisional heating and cooling mechanisms and the toroidal pumping effect. (author)

Experimental Study of the Weptos Wave Energy Converter

DEFF Research Database (Denmark)

Pecher, Arthur; Kofoed, Jens Peter; Larsen, Tommy

2012-01-01

This paper presents the power performance results of the experimental study of the WEPTOS wave energy converter (WEC). This novel device combines an established and efficient wave energy absorbing mechanism with an adjustable structure that can regulate the amount of incoming wave energy and reduce...... loads in extreme wave conditions. This A-shaped floating structure absorbs the energy in the waves through a multitude of rotors, the shape of which is based on the renowned Salter’s Duck. These rotors pivot around a common axle, one for each leg of the structure, to which the rotors transfer...... the absorbed wave energy and which is connected to a common power take off system (one for each leg). The study investigates the performance of the device in a large range of wave states and estimates the performance in terms of mechanical power available to the power take off system of the WEPTOS WEC for two...

Near-Shore Floating Wave Energy Converters

DEFF Research Database (Denmark)

Ruol, Piero; Zanuttigh, Barbara; Martinelli, Luca

2011-01-01

and transmission characteristics are approximated to functions of wave height, period and obliquity. Their order of magnitude are 20% and 80%, respectively. It is imagined that an array of DEXA is deployed in front of Marina di Ravenna beach (IT), a highly touristic site of the Adriatic Coast. Based on the CERC......Aim of this note is to analyse the possible application of a Wave Energy Converter (WEC) as a combined tool to protect the coast and harvest energy. Physical model tests are used to evaluate wave transmission past a near-shore floating WEC of the wave activated body type, named DEXA. Efficiency...

Preliminary Analysis of a Submerged Wave Energy Device

Science.gov (United States)

Wagner, J. R.; Wagner, J. J.; Hayatdavoodi, M.; Ertekin, R. C.

2016-02-01

Preliminary analysis of a submerged wave energy harvesting device is presented. The device is composed of a thin, horizontally submerged plate that is restricted to heave oscillations under the influence of surface waves. The submerged plate is oscillating, and it can be attached to a fixed rotor, or a piston, to harvest the wave energy. A fully submerged wave energy converter is preferred over a surface energy convertor due to its durability and less visual and physical distractions it presents. In this study, the device is subject to nonlinear shallow-water waves. Wave loads on the submerged oscillating plate are obtained via the Level I Green-Naghdi equations. The unsteady motion of the plate is obtained by solving the nonlinear equations of motion. The results are obtained for a range of waves with varying heights and periods. The amplitude and period of plate oscillations are analyzed as functions of the wave parameters and plate width. Particular attention is given to the selection of the site of desired wave field. Initial estimation on the amount of energy extraction from the device, located near shore at a given site, is provided.

Ocean floor mounting of wave energy converters

Science.gov (United States)

Siegel, Stefan G

2015-01-20

A system for mounting a set of wave energy converters in the ocean includes a pole attached to a floor of an ocean and a slider mounted on the pole in a manner that permits the slider to move vertically along the pole and rotate about the pole. The wave energy converters can then be mounted on the slider to allow adjustment of the depth and orientation of the wave energy converters.

Practical performances of MPC for wave energy converters

DEFF Research Database (Denmark)

Ferri, Francesco; Tetu, Amelie; Hals, J.

2016-01-01

Maximising the efficiency of Wave Energy Converter (WEC) is one of the important tasks toward the exploitation of the wave energy resource. Along with a proper design of the device, an important way to achieve better energy performances is to improve the wave-body interaction by applying an appro...

S-Matrix to potential inversion of low-energy α-12C phase shifts

Science.gov (United States)

Cooper, S. G.; Mackintosh, R. S.

1990-10-01

The IP S-matrix to potential inversion procedure is applied to phase shifts for selected partial waves over a range of energies below the inelastic threshold for α-12C scattering. The phase shifts were determined by Plaga et al. Potentials found by Buck and Rubio to fit the low-energy alpha cluster resonances need only an increased attraction in the surface to accurately reproduce the phase-shift behaviour. Substantial differences between the potentials for odd and even partial waves are necessary. The surface tail of the potential is postulated to be a threshold effect.

Model Testing of the Wave Energy Converter Seawave Slot-Cone Generator

DEFF Research Database (Denmark)

Kofoed, Jens Peter

This report presents the results of a preliminary experimental study of the wave energy convert (WEC) Seawave Slot-Cone Generator (SSG). SSG is a WEC utilizing wave overtopping in multiple reservoirs. In the present SSG setup three reservoirs has been used. Model tests have been performed using...... a scale model (length scale 1:15) of a SSG device to be installed on the west coast of the island Kvitsøy near Stavanger, Norway. The tests were carried out at Dept. of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The model has been subjected to regular and irregular waves...... corresponding to typical conditions off shore from the intended installation site. The overtopping rates for the individual reservoirs have been measured and the potential energy in the overtopping water has been calculated....

Wave energy conversion utilizing vertical motion of water in the array of water chambers aligned in the direction of wave propagation

Directory of Open Access Journals (Sweden)

Kesayoshi Hadano

2017-05-01

Full Text Available As a new technical approach, wave energy converter by using vertical motion of water in the multiple water chambers were developed to realize actual wave power generation as eco-environmental renewable energy. And practical use of wave energy converter was actually to require the following conditions: (1 setting up of the relevant device and its application to wave power generation in case that severe wave loading is avoided; (2 workability in installation and maintenance operations; (3 high energy conversion potential; and (4 low cost. In this system, neither the wall(s of the chambers nor the energy conversion device(s are exposed to the impulsive load due to water wave. Also since this system is profitable when set along the jetty or along a long floating body, installation and maintenance are done without difficulty and the cost is reduced. In this paper, we describe the system which consists of a float, a shaft connected with another shaft, a rack and pinion arrangement, a ratchet mechanism, and rotary type generator(s. Then, we present the dynamics model for evaluating the output electric power, and the results of numerical calculation including the effect of the phase shift of up/down motion of the water in the array of water chambers aligned along the direction of wave propagation.

Performance of a Tethered Point Wave-Energy Absorber in Regular and Irregular Waves

KAUST Repository

Bachynski, Erin E.; Young, Yin Lu; Yeung, Ronald W.

2010-01-01

The importance of the mooring system on the dynamic response of a point-absorber type ocean-wave energy converter (WEC) is investigated using a frequency-domain approach. In order to ensure the safety of WECs, careful consideration of the response and resonance frequencies in all motions must be evaluated, including the effects of the mooring system. In this study, a WEC floater with a closed, flat bottom is modeled as a rigid vertical cylinder tethered by elastic mooring lines. The WEC hydrodynamic added mass and damping are obtained using established potential-flow methods, with additional damping provided by the energy-extraction system. The results show that the response of the WEC, and the corresponding power takeoff, varies with the diameter-to-draft (D=T) ratio, mooring system stiffness, and mass distribution. For a given wave climate in Northern California, near San Francisco, the heave energy extraction is found to be best for a shallow WEC with a soft mooring system, compared to other systems that were examined. This result assumes a physical limit (cap) on the motion which is related to the significant wave height to draft ratio. Shallow draft designs, however, may experience excessive pitch motions and relatively larger viscous damping. In order to mitigate the pitch response, the pitch radius of gyration should be small and the center of mass should be low. Copyright © 2010 by ASME.

Potential energy surface from spectroscopic data in the photodissociation of polyatomic molecules

International Nuclear Information System (INIS)

Kim, Hwa Joong; Kim, Young Sik

2001-01-01

The time-dependent tracking inversion method is studied to extract the potential energy surface of the electronic excited state in the photodissociation of triatomic molecules. Based on the relay of the regularized inversion procedure and time-dependent wave packet propagation, the algorithm extracts the underlying potential energy surface piece by tracking the time-dependent data, which can be synthesized from Raman excitation profiles. We have demonstrated the algorithm to extract the potential energy surface of electronic excited state for NO 2 molecule where the wave packet split on a saddle-shaped surface. Finally, we describe the merits of the time-dependent tracking inversion method compared with the time-dependent inversion method and discussed several extensions of the algorithm

Image processing to optimize wave energy converters

Science.gov (United States)

Bailey, Kyle Marc-Anthony

The world is turning to renewable energies as a means of ensuring the planet's future and well-being. There have been a few attempts in the past to utilize wave power as a means of generating electricity through the use of Wave Energy Converters (WEC), but only recently are they becoming a focal point in the renewable energy field. Over the past few years there has been a global drive to advance the efficiency of WEC. Placing a mechanical device either onshore or offshore that captures the energy within ocean surface waves to drive a mechanical device is how wave power is produced. This paper seeks to provide a novel and innovative way to estimate ocean wave frequency through the use of image processing. This will be achieved by applying a complex modulated lapped orthogonal transform filter bank to satellite images of ocean waves. The complex modulated lapped orthogonal transform filterbank provides an equal subband decomposition of the Nyquist bounded discrete time Fourier Transform spectrum. The maximum energy of the 2D complex modulated lapped transform subband is used to determine the horizontal and vertical frequency, which subsequently can be used to determine the wave frequency in the direction of the WEC by a simple trigonometric scaling. The robustness of the proposed method is provided by the applications to simulated and real satellite images where the frequency is known.

Specification of Instrumentation of Multi MW Wave Dragon Offshore Wave Energy Converter

DEFF Research Database (Denmark)

Gilling, Lasse; Kofoed, Jens Peter

Wave Dragon is a wave energy converter of the overtopping type and is described e.g. in Tedd et. al. (2006). The device has been thoroughly tested on a 1:51.8 scale model in wave laboratories and a 1:4.5 scale model deployed in Nissum Bredning, a large inland waterway in Denmark. Based on the exp......Wave Dragon is a wave energy converter of the overtopping type and is described e.g. in Tedd et. al. (2006). The device has been thoroughly tested on a 1:51.8 scale model in wave laboratories and a 1:4.5 scale model deployed in Nissum Bredning, a large inland waterway in Denmark. Based...

Mathematical Modeling of Oscillating Water Columns Wave-Structure Interaction in Ocean Energy Plants

Directory of Open Access Journals (Sweden)

Aitor J. Garrido

2015-01-01

Full Text Available Oscillating Water Column (OWC-based power take-off systems are one of the potential solutions to the current energy problems arising from the use of nuclear fission and the consumption of fossil fuels. This kind of energy converter turns wave energy into electric power by means of three different stages: firstly wave energy is transformed into pneumatic energy in the OWC chamber, and then a turbine turns it into mechanical energy and finally the turbogenerator module attached to the turbine creates electric power from the rotational mechanical energy. To date, capture chambers have been the least studied part. In this context, this paper presents an analytical model describing the dynamic behavior of the capture chamber, encompassing the wave motion and its interaction with the OWC structure and turbogenerator module. The model is tested for the case of the Mutriku wave power plant by means of experimental results. For this purpose, representative case studies are selected from wave and pressure drop input-output data. The results show an excellent matching rate between the values predicted by the model and the experimental measured data with a small bounded error in all cases, so that the validity of the proposed model is proven.

Experimental Research of a New Wave Energy Conversion Device

Science.gov (United States)

Lu, Zhongyue; Shang, Jianzhong; Luo, Zirong; Sun, Chongfei; Chen, Gewei

2018-01-01

With the increasing tension of contemporary social energy, the development and utilization of renewable energy has become an important development direction. As an important part of renewable energy, wave energy has the characteristics of green environmental protection and abundant reserves, attracting more investment and research. For small marine equipment energy supply problem, this paper puts forward a micro wave energy conversion device as the basic of heaving motion of waves in the ocean. This paper designed a new type of power output device can solve the micro wave energy conversion problem.

Theoretical studies of potential energy surfaces and computational methods

Energy Technology Data Exchange (ETDEWEB)

Shepard, R. [Argonne National Laboratory, IL (United States)

1993-12-01

This project involves the development, implementation, and application of theoretical methods for the calculation and characterization of potential energy surfaces involving molecular species that occur in hydrocarbon combustion. These potential energy surfaces require an accurate and balanced treatment of reactants, intermediates, and products. This difficult challenge is met with general multiconfiguration self-consistent-field (MCSCF) and multireference single- and double-excitation configuration interaction (MRSDCI) methods. In contrast to the more common single-reference electronic structure methods, this approach is capable of describing accurately molecular systems that are highly distorted away from their equilibrium geometries, including reactant, fragment, and transition-state geometries, and of describing regions of the potential surface that are associated with electronic wave functions of widely varying nature. The MCSCF reference wave functions are designed to be sufficiently flexible to describe qualitatively the changes in the electronic structure over the broad range of geometries of interest. The necessary mixing of ionic, covalent, and Rydberg contributions, along with the appropriate treatment of the different electron-spin components (e.g. closed shell, high-spin open-shell, low-spin open shell, radical, diradical, etc.) of the wave functions, are treated correctly at this level. Further treatment of electron correlation effects is included using large scale multireference CI wave functions, particularly including the single and double excitations relative to the MCSCF reference space. This leads to the most flexible and accurate large-scale MRSDCI wave functions that have been used to date in global PES studies.

Resonant Wave Energy Converters: Concept development

International Nuclear Information System (INIS)

Arena, Felice; Barbaro, Giuseppe; Fiamma, Vincenzo; Laface, Valentina; Malara, Giovanni; Romolo, Alessandra; Strati, Federica Mara

2015-01-01

The Resonant Wave Energy Converter (REWEC) is a device for converting sea wave energy to electrical energy. It belongs to the family of Oscillating Water Columns and is composed by an absorbing chamber connected to the open sea via a vertical duct. The paper gives a holistic view on the concept development of the device, starting from its implementation in the context of submerged breakwaters to the recently developed vertical breakwaters. [it

Highly Adaptive Solid-Liquid Interfacing Triboelectric Nanogenerator for Harvesting Diverse Water Wave Energy.

Science.gov (United States)

Zhao, Xue Jiao; Kuang, Shuang Yang; Wang, Zhong Lin; Zhu, Guang

2018-05-22

Harvesting water wave energy presents a significantly practical route to energy supply for self-powered wireless sensing networks. Here we report a networked integrated triboelectric nanogenerator (NI-TENG) as a highly adaptive means of harvesting energy from interfacing interactions with various types of water waves. Having an arrayed networking structure, the NI-TENG can accommodate diverse water wave motions and generate stable electric output regardless of how random the water wave is. Nanoscaled surface morphology consisting of dense nanowire arrays is the key for obtaining high electric output. A NI-TENG having an area of 100 × 70 mm 2 can produce a stable short-circuit current of 13.5 μA and corresponding electric power of 1.03 mW at a water wave height of 12 cm. This merit promises practical applications of the NI-TENG in real circumstances, where water waves are highly variable and unpredictable. After energy storage, the generated electric energy can drive wireless sensing by autonomously transmitting data at a period less than 1 min. This work proposes a viable solution for powering individual standalone nodes in a wireless sensor network. Potential applications include but are not limited to long-term environment monitoring, marine surveillance, and off-shore navigation.

Energy Transfer in Scattering by Rotating Potentials

Indian Academy of Sciences (India)

Quantum mechanical scattering theory is studied for time-dependent Schrödinger operators, in particular for particles in a rotating potential. Under various assumptions about the decay rate at infinity we show uniform boundedness in time for the kinetic energy of scattering states, existence and completeness of wave ...

Wave Dissipation on Low- to Super-Energy Coral Reefs

Science.gov (United States)

Harris, D. L.

2016-02-01

Coral reefs are valuable, complex and bio-diverse ecosystems and are also known to be one of the most effective barriers to swell events in coastal environments. Previous research has found coral reefs to be remarkably efficient in removing most of the wave energy during the initial breaking and transformation on the reef flats. The rate of dissipation is so rapid that coral reefs have been referred to as rougher than any known coastal barrier. The dissipation of wave energy across reef flats is crucial in maintaining the relatively low-energy conditions in the back reef and lagoonal environments providing vital protection to adjacent beach or coastal regions from cyclone and storm events. A shift in the regulation of wave energy by reef flats could have catastrophic consequences ecologically, socially, and economically. This study examined the dissipation of wave energy during two swell events in Tahiti and Moorea, French Polyesia. Field sites were chosen in varying degrees of exposure and geomorphology from low-energy protected sites (Tiahura, Moorea) to super-energy sites (Teahupo'o, Tahiti). Waves were measured during two moderate to large swell events in cross reef transects using short-term high-resolution pressure transducers. Wave conditions were found to be similar in all back reef locations despite the very different wave exposure at each reef site. However, wave conditions on the reef flats were different and mirrored the variation in wave exposure with depth over the reef flat the primary regulator of reef flat wave height. These results indicate that coral reef flats evolve morphodynamically with the wave climate, which creates coral reef geomorphologies capable of dissipating wave energy that results in similar back reef wave conditions regardless of the offshore wave climate.

Hydraulic Evaluation of the Crest Wing Wave Energy Converter

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Antonishen, Michael Patrick

This report presents the results of an experimental study of the wave energy converting abilities of the Crest Wing wave energy converter (WEC). The Crest Wing is a WEC that uses its movement in matching the shape of an oncoming wave to generate power. Model tests have been performed using a scale...... model (length scale 1:30), provided by WaveEnergyFyn, in regular and irregular wave states that can be found in Assessment of Wave Energy Devices. Best Practice as used in Denmark (Frigaard et al., 2008). The tests were carried out at Dept. of Civil Engineering, Aalborg (Frigaard et al., 2008......). The tests were carried out at Dept. of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The displacement and force applied to a power take off system, provided by WaveEnergyFyn, were measured and used to calculate total power take off....

The SSG Wave Energy Converter: Performance, Status and Recent Developments

Directory of Open Access Journals (Sweden)

Mariano Buccino

2012-01-01

Full Text Available The Sea-wave Slot-cone Generator (SSG is a Wave Energy Converter based on the wave overtopping principle; it employs several reservoirs placed on top of each other, in which the energy of incoming waves is stored as potential energy. Then, the captured water runs through turbines for electricity production. The system works under a wide spectrum of different wave conditions, giving a high overall efficiency. It can be suitable for shoreline and breakwater applications and presents particular advantages, such as sharing structure costs, availability of grid connection and recirculation of water inside the harbor, as the outlet of the turbines is on the rear part of the system. Recently, plans for the SSG pilot installations are in progress at the Svaaheia site (Norway, the port of Hanstholm (Denmark and the port of Garibaldi (Oregon, USA. In the last-mentioned two projects, the Sea-wave Slot-cone Generator technology is integrated into the outer harbor breakwater and jetty reconstruction projects. In the last years extensive studies have been performed on the hydraulic and the structural response of this converter, with the aim of optimizing the design process. The investigations have been conducted by physical model tests and numerical simulations and many results have been published on both conference proceedings and journals. The main scope of this paper is reviewing the most significant findings, to provide the reader with an organic overview on the present status of knowledge.

Sensitivity of wave energy to climate change

OpenAIRE

Harrison, Gareth; Wallace, Robin

2005-01-01

Wave energy will have a key role in meeting renewable energy targets en route to a low carbon economy. However, in common with other renewables, it may be sensitive to changes in climate resulting from rising carbon emissions. Changes in wind patterns are widely anticipated and this will ultimately alter wave regimes. Indeed, evidence indicates that wave heights have been changing over the last 40 years, although there is no proven link to global warming. Changes in the wave climate will impa...

Modelling of the Overtopping Flow on the Wave Dragon Wave Energy Converter

DEFF Research Database (Denmark)

Parmeggiani, Stefano; Pecher, Arthur; Kofoed, Jens Peter

2010-01-01

The Wave Dragon is a floating slack-moored Wave Energy Converter of the overtopping type, which is facing now the last phase of development before the commercial exploitation: the deployment of a full-scale demonstrator. In this phase a modelling tool allowing for accurate predictions of the perf......The Wave Dragon is a floating slack-moored Wave Energy Converter of the overtopping type, which is facing now the last phase of development before the commercial exploitation: the deployment of a full-scale demonstrator. In this phase a modelling tool allowing for accurate predictions...

Experimental Modelling of the Overtopping Flow on the Wave Dragon Wave Energy Converter

DEFF Research Database (Denmark)

Parmeggiani, Stefano; Kofoed, Jens Peter

The Wave Dragon is a floating slack-moored Wave Energy Converter (WEC) of the overtopping type. Oncoming waves are focused by two wing reflectors towards the ramp of the device, surge-up and overtop into a reservoir placed at a higher level than the surface of the sea. The energy production takes...

The Indian wave energy programme- an overview

International Nuclear Information System (INIS)

Ravindran, M.; Jayashankar, V.; Jalihal, P.; Pathak, A.G.

1997-01-01

The Indian wave energy plant at Vizhinjam, Kerala has demonstrated that energy from a random source such as waves can be harnessed as electrical energy and exported via the local grid. This plant is based on the oscillating water column (OWC) principle. The research on wave energy in India has achieved a commendable status within a decade. A caisson was constructed in December 1990 at Vizhinjam and two generations of power modules have been tested as of today. The physical processes in the energy conversion are understood to a much greater extent, leading to a threefold increase in absolute power from the plant. Efforts are on to make the technology cost-effective

Wave Runup on a Frozen Beach Under High Energy Conditions

Science.gov (United States)

Didier, D.; Bernatchez, P.; Dumont, D.; Corriveau, M.

2017-12-01

High and mid-latitude beaches have typical morphological characteristics influenced by nearshore processes prevailing under ice conditions during cold season. Nearshore ice complexes (NIC) offer a natural coastal protection by covering beach sediments, while offshore ice-infested waters dissipate incoming waves. Climate change contributes to sea ice shrinking therefore reducing its protection against erosion and flooding. In the Estuary and Gulf of the St. Lawrence (ESL, GSL) (eastern Canada), sea ice cover undergoes an overall shrinking and simulated future projections tend toward a negligible effect on wave climate by 2100. Quantifying the effect of nearshore dynamics on frozen beaches is therefore imperative for coastal management as more wave energy at the coast is expected in the future. To measure the effect of a frozen beach on wave runup elevations, this study employs a continuous video recording of the swash motion at 4Hz. Video-derived wave runup statistics have been extracted during a tidal cycle on a frozen beach, using the Pointe-Lebel beach (ESL) as a test case. Timestack analysis was combined with offshore water levels and wave measurements. A comparison of runup under icy conditions (Dec. 30 2016) with a runup distribution during summer was made under similar high energy wave conditions. Results indicate high runup excursions potentially caused by lowered sediment permeability due to high pore-ice saturation in the swash zone, accentuating the overwash of the eroding coastline and thus the risk of flooding. With projected reduction in coastal sea ice cover and thus higher wave energy, this study suggests that episodes of degradation and weakening could influence the coastal flood risk in mid- and high-latitude cold environments.

Wave power - Sustainable energy or environmentally costly? A review with special emphasis on linear wave energy converters

Energy Technology Data Exchange (ETDEWEB)

Langhamer, Olivia [Dept. of Animal Ecology, UU, Norbyvaegen 18D, S-75236 Uppsala (Sweden); Swedish Centre for Renewable Electric Energy Conversion, Division for Electricity, Aangstroem Laboratory, Uppsala University, Box 534, S-75121 Uppsala (Sweden); Haikonen, Kalle; Sundberg, Jan [Swedish Centre for Renewable Electric Energy Conversion, Division for Electricity, Aangstroem Laboratory, Uppsala University, Box 534, S-75121 Uppsala (Sweden)

2010-05-15

Generating electricity from waves is predicted to be a new source of renewable energy conversion expanding significantly, with a global potential in the range of wind and hydropower. Several wave power techniques are on the merge of commercialisation, and thus evoke questions of environmental concern. Conservation matters are to some extent valid independent of technique but we mainly focus on point absorbing linear generators. By giving examples from the Lysekil project, run by Uppsala University and situated on the Swedish west coast, we demonstrate ongoing and future environmental studies to be performed along with technical research and development. We describe general environmental aspects generated by wave power projects; issues also likely to appear in Environmental Impact Assessment studies. Colonisation patterns and biofouling are discussed with particular reference to changes of the seabed and alterations due to new substrates. A purposeful artificial reef design to specially cater for economically important or threatened species is also discussed. Questions related to fish, fishery and marine mammals are other examples of topics where, e.g. no-take zones, marine bioacoustics and electromagnetic fields are important areas. In this review we point out areas in which studies likely will be needed, as ventures out in the oceans also will give ample opportunities for marine environmental research in general and in areas not previously studied. Marine environmental and ecological aspects appear to be unavoidable for application processes and in post-deployment studies concerning renewable energy extraction. Still, all large-scale renewable energy conversion will cause some impact mainly by being area demanding. An early incorporation of multidisciplinary and high quality research might be a key for new ocean-based techniques. (author)

Energy partition, scale by scale, in magnetic Archimedes Coriolis weak wave turbulence.

Science.gov (United States)

Salhi, A; Baklouti, F S; Godeferd, F; Lehner, T; Cambon, C

2017-02-01

Magnetic Archimedes Coriolis (MAC) waves are omnipresent in several geophysical and astrophysical flows such as the solar tachocline. In the present study, we use linear spectral theory (LST) and investigate the energy partition, scale by scale, in MAC weak wave turbulence for a Boussinesq fluid. At the scale k^{-1}, the maximal frequencies of magnetic (Alfvén) waves, gravity (Archimedes) waves, and inertial (Coriolis) waves are, respectively, V_{A}k,N, and f. By using the induction potential scalar, which is a Lagrangian invariant for a diffusionless Boussinesq fluid [Salhi et al., Phys. Rev. E 85, 026301 (2012)PLEEE81539-375510.1103/PhysRevE.85.026301], we derive a dispersion relation for the three-dimensional MAC waves, generalizing previous ones including that of f-plane MHD "shallow water" waves [Schecter et al., Astrophys. J. 551, L185 (2001)AJLEEY0004-637X10.1086/320027]. A solution for the Fourier amplitude of perturbation fields (velocity, magnetic field, and density) is derived analytically considering a diffusive fluid for which both the magnetic and thermal Prandtl numbers are one. The radial spectrum of kinetic, S_{κ}(k,t), magnetic, S_{m}(k,t), and potential, S_{p}(k,t), energies is determined considering initial isotropic conditions. For magnetic Coriolis (MC) weak wave turbulence, it is shown that, at large scales such that V_{A}k/f≪1, the Alfvén ratio S_{κ}(k,t)/S_{m}(k,t) behaves like k^{-2} if the rotation axis is aligned with the magnetic field, in agreement with previous direct numerical simulations [Favier et al., Geophys. Astrophys. Fluid Dyn. (2012)] and like k^{-1} if the rotation axis is perpendicular to the magnetic field. At small scales, such that V_{A}k/f≫1, there is an equipartition of energy between magnetic and kinetic components. For magnetic Archimedes weak wave turbulence, it is demonstrated that, at large scales, such that (V_{A}k/N≪1), there is an equipartition of energy between magnetic and potential components

Wave energy resource assessment and review of the technologies

Energy Technology Data Exchange (ETDEWEB)

Wan Nik, W.B.: Sulaiman, O.O. [Maritime Technology Department, Universiti Malaysia Terengganu, 21030, Kuala Terengganu (Malaysia); Rosliza, R. [TATI University College, Teluk Kalong, 24000 Kemaman, Terengganu, (Malaysia); Prawoto, Y. [Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 UTM, Skudai, Johor (Malaysia); Muzathik, A.M. [Institute of Technology, University of Moratuwa (Sri Lanka)

2011-07-01

Increase in human population has increased the demand for more energy. Technical improvement in transport and electrical appliances gives a lot of facilities to our life nowadays. Still we need to generate or convert this energy. Energy generation based on conventional technologies is always accompanied by environmental pollution. It gives overheating and greenhouse effects that later result in biosphere degradation. Nowadays sea wave energy is being increasingly regarded in many countries as a major and promising resource. It is renewable and environmentally friendly. In this paper wave parameters related to wave energy is analyzed. Then the paper describes the development of many different types of wave-energy converters. Several topics are addressed; the characterization of the wave energy resource, range of devices and how such devices can be organized into classes.

Hydrodynamic Characteristics and Strength Analysis of a Novel Dot-matrix Oscillating Wave Energy Converter

Science.gov (United States)

Shao, Meng; Xiao, Chengsi; Sun, Jinwei; Shao, Zhuxiao; Zheng, Qiuhong

2017-12-01

The paper analyzes hydrodynamic characteristics and the strength of a novel dot-matrix oscillating wave energy converter, which is in accordance with nowadays’ research tendency: high power, high efficiency, high reliability and low cost. Based on three-dimensional potential flow theory, the paper establishes motion control equations of the wave energy converter unit and calculates wave loads and motions. On this basis, a three-dimensional finite element model of the device is built to check its strength. Through the analysis, it can be confirmed that the WEC is feasible and the research results could be a reference for wave energy’s exploration and utilization.

Initial Assessment of Mooring Solutions for Floating Wave Energy Converters

DEFF Research Database (Denmark)

Thomsen, Jonas Bjerg; Kofoed, Jens Peter; Delaney, Martin

2016-01-01

The present study investigates three different types of mooring systems in order to establish potential cost reductions and applicability to wave energy converters (WECs). Proposed mooring systems for three existing WECs create the basis for this study, and the study highlights areas of interest ...

Wave energy budget analysis in the Earth’s radiation belts uncovers a missing energy

Science.gov (United States)

Artemyev, A.V.; Agapitov, O.V.; Mourenas, D.; Krasnoselskikh, V.V.; Mozer, F.S.

2015-01-01

Whistler-mode emissions are important electromagnetic waves pervasive in the Earth’s magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and the upper-atmosphere ionization or chemical composition. Here, we report an analysis of 10-year Cluster data, statistically evaluating the full wave energy budget in the Earth’s magnetosphere, revealing that a significant fraction of the energy corresponds to hitherto generally neglected very oblique waves. Such waves, with 10 times smaller magnetic power than parallel waves, typically have similar total energy. Moreover, they carry up to 80% of the wave energy involved in wave–particle resonant interactions. It implies that electron heating and precipitation into the atmosphere may have been significantly under/over-valued in past studies considering only conventional quasi-parallel waves. Very oblique waves may turn out to be a crucial agent of energy redistribution in the Earth’s radiation belts, controlled by solar activity. PMID:25975615

Direct Drive Wave Energy Buoy

Energy Technology Data Exchange (ETDEWEB)

Rhinefrank, Kenneth [Columbia Power Technologies, Inc., Charlottesville, VA (United States); Lamb, Bradford [Columbia Power Technologies, Inc., Charlottesville, VA (United States); Prudell, Joseph [Columbia Power Technologies, Inc., Charlottesville, VA (United States); Hammagren, Erik [Columbia Power Technologies, Inc., Charlottesville, VA (United States); Lenee-Bluhm, Pukha [Columbia Power Technologies, Inc., Charlottesville, VA (United States)

2016-08-22

This Project aims to satisfy objectives of the DOE’s Water Power Program by completing a system detailed design (SDD) and other important activities in the first phase of a utility-scale grid-connected ocean wave energy demonstration. In early 2012, Columbia Power (CPwr) had determined that further cost and performance optimization was necessary in order to commercialize its StingRAY wave energy converter (WEC). CPwr’s progress toward commercialization, and the requisite technology development path, were focused on transitioning toward a commercial-scale demonstration. This path required significant investment to be successful, and the justification for this investment required improved annual energy production (AEP) and lower capital costs. Engineering solutions were developed to address these technical and cost challenges, incorporated into a proposal to the US Department of Energy (DOE), and then adapted to form the technical content and statement of project objectives of the resulting Project (DE-EE0005930). Through Project cost-sharing and technical collaboration between DOE and CPwr, and technical collaboration with Oregon State University (OSU), National Renewable Energy Lab (NREL) and other Project partners, we have demonstrated experimentally that these conceptual improvements have merit and made significant progress towards a certified WEC system design at a selected and contracted deployment site at the Wave Energy Test Site (WETS) at the Marine Corps Base in Oahu, HI (MCBH).

Wave energy absorption by ducks

OpenAIRE

Kurniawan, Adi

2017-01-01

We study the absorption of wave energy by a single and multiple cam-shaped bodies referred to as ducks. Numerical models are developed under the assumptions of linear theory. We consider wave absorption by a single duck as well as by two lines of ducks meeting at an angle.

Wave energy absorption by ducks

DEFF Research Database (Denmark)

Kurniawan, Adi

2018-01-01

We study the absorption of wave energy by a single and multiple cam-shaped bodies referred to as ducks. Numerical models are developed under the assumptions of linear theory. We consider wave absorption by a single duck as well as by two lines of ducks meeting at an angle....

Feasibility study of tuned liquid column damper for ocean wave energy extraction

Science.gov (United States)

Wong, Yihong; King, Yeong-Jin; Lai, An-Chow; Chong, Kok-Keong; Lim, Boon-Han

2017-04-01

Intermittent nature and low efficiency are the major issues in renewable energy supply. To overcome these issues, one of the possible methods is through a hybrid system where multiple sources of renewable energy are combined to compensate each other's weaknesses. The hybrid of solar energy and wave energy becomes possible through the introduction of a stable floating platform which enables solar energy generation above it and wave energy harvesting underneath it. This paper is intended to study the feasibility of harnessing ocean wave energy using a tuned liquid column damper (TLCD), a type of passive damping device that is designed to suppress externally induced vibration force at a specific frequency range. The proposed TLCD is to be implemented within a floating offshore structure to serve as a vibration mitigating mechanism by reducing the dynamic response of the structure and simultaneously utilize the flowing motion of liquid within the TLCD for generating electricity. The constructed TLCD prototype is tuned according to theoretical study and tested using a shaking table with a predetermined frequency range. The oscillating motion of water within the TLCD and the potential of installation of hydro turbine generator in term of recoverable amount of energy are studied.

Air Turbines for Wave Energy Conversion

Directory of Open Access Journals (Sweden)

Manabu Takao

2012-01-01

Full Text Available This paper describes the present status of the art on air turbines, which could be used for wave energy conversion. The air turbines included in the paper are as follows: Wells type turbines, impulse turbines, radial turbines, cross-flow turbine, and Savonius turbine. The overall performances of the turbines under irregular wave conditions, which typically occur in the sea, have been compared by numerical simulation and sea trial. As a result, under irregular wave conditions it is found that the running and starting characteristics of the impulse type turbines could be superior to those of the Wells turbine. Moreover, as the current challenge on turbine technology, the authors explain a twin-impulse turbine topology for wave energy conversion.

An innovative approach for energy generation from waves

Energy Technology Data Exchange (ETDEWEB)

Al-Habaibeh, A. [Advanced Design and Manufacturing Engineering Centre, School of Architecture, Design and the Built Environment, Nottingham Trent University (United Kingdom); Su, D. [School of Architecture, Design and the Built Environment, Nottingham Trent University (United Kingdom); McCague, J. [Technical Director, Ocean Navitas Ltd., Lincolnshire (United Kingdom); Knight, A. [Marketing and Communications Manager, Ocean Navitas Ltd., Lincolnshire (United Kingdom)

2010-08-15

Sustainable energy generation is becoming increasingly important due to the expected limitations in current energy resources and to reduce pollution. Wave energy generation has seen significant development in recent years. This paper describes an innovative system for generating energy from wave power. A complete description of the system is presented including the general concept, configurations, mechanical design, electrical system, simulation techniques and expected power output of the system. The results from the hydraulic linear wave simulator, using a real wave profiles captured at a location in the UK using an ultrasound system, it was seen that a {+-}0.8 m wave at 10 s time period, produced a conditioned power output of approximately 22 kW at optimum load conditions for the tested 3-phase 44 kW permanent magnet generator type STK500. The results indicate that this new technology could provide an efficient and low cost method of generating electricity from waves. (author)

An innovative approach for energy generation from waves

International Nuclear Information System (INIS)

Al-Habaibeh, A.; Su, D.; McCague, J.; Knight, A.

2010-01-01

Sustainable energy generation is becoming increasingly important due to the expected limitations in current energy resources and to reduce pollution. Wave energy generation has seen significant development in recent years. This paper describes an innovative system for generating energy from wave power. A complete description of the system is presented including the general concept, configurations, mechanical design, electrical system, simulation techniques and expected power output of the system. The results from the hydraulic linear wave simulator, using a real wave profiles captured at a location in the UK using an ultrasound system, it was seen that a ±0.8 m wave at 10 s time period, produced a conditioned power output of approximately 22 kW at optimum load conditions for the tested 3-phase 44 kW permanent magnet generator type STK500. The results indicate that this new technology could provide an efficient and low cost method of generating electricity from waves.

Electron-temperature-gradient-driven drift waves and anomalous electron energy transport

International Nuclear Information System (INIS)

Shukla, P.K.; Murtaza, G.; Weiland, J.

1990-01-01

By means of a kinetic description for ions and Braginskii's fluid model for electrons, three coupled nonlinear equations governing the dynamics of low-frequency short-wavelength electrostatic waves in the presence of equilibrium density temperature and magnetic-field gradients in a two-component magnetized plasma are derived. In the linear limit a dispersion relation that admits new instabilities of drift waves is presented. An estimate of the anomalous electron energy transport due to non-thermal drift waves is obtained by making use of the saturated wave potential, which is deduced from the mixing-length hypothesis. Stationary solutions of the nonlinear equations governing the interaction of linearly unstable drift waves are also presented. The relevance of this investigation to wave phenomena in space and laboratory plasmas is pointed out. (author)

Experimental Study on the Langlee Wave Energy Converter

DEFF Research Database (Denmark)

Lavelle, John; Kofoed, Jens Peter

This report concerns the experimental study of the 1:20 scale model of the Langlee Wave Energy Converter (WEC) carried out at Aalborg University’s wave basin during the summer of 2010.......This report concerns the experimental study of the 1:20 scale model of the Langlee Wave Energy Converter (WEC) carried out at Aalborg University’s wave basin during the summer of 2010....

Power Generation Using Mechanical Wave Energy Converter

Directory of Open Access Journals (Sweden)

Srinivasan Chandrasekaran

2012-03-01

Full Text Available Ocean wave energy plays a significant role in meeting the growing demand of electric power. Economic, environmental, and technical advantages of wave energy set it apart from other renewable energy resources. Present study describes a newly proposed Mechanical Wave Energy Converter (MEWC that is employed to harness heave motion of floating buoy to generate power. Focus is on the conceptual development of the device, illustrating details of component level analysis. Employed methodology has many advantages such as i simple and easy fabrication; ii easy to control the operations during rough weather; and iii low failure rate during normal sea conditions. Experimental investigations carried out on the scaled model of MWEC show better performance and its capability to generate power at higher efficiency in regular wave fields. Design Failure Mode and Effect Analysis (FMEA shows rare failure rates for all components except the floating buoy.

Reliability Study of Energy Harvesting from Sea Waves by Piezoelectric Patches Consideraing Random JONSWAP Wave Theory

Directory of Open Access Journals (Sweden)

M. Ettefagh

2018-03-01

Full Text Available One of the new methods for powering low-power electronic devices employed in the sea, is using of mechanical energies of sea waves. In this method, piezoelectric material is employed to convert the mechanical energy of sea waves into electrical energy. The advantage of this method is based on not implementing the battery charging system. Although, many studies have been done about energy harvesting from sea waves, energy harvesting with considering random JONWSAP wave theory is not fully studied up to now. The random JONSWAP wave model is a more realistic approximation of sea waves in comparison of Airy wave model. Therefore, in this paper a vertical beam with the piezoelectric patches, which is fixed to the seabed, is considered as energy harvester system. The energy harvesting system is simulated by MATLAB software, and then the vibration response of the beam and consequently the generated power is obtained considering the JONWSAP wave theory. In addition, the reliability of the system and the effect of piezoelectric patches uncertainties on the generated power are studied by statistical method. Furthermore, the failure possibility of harvester based on violation criteria is investigated.  

Critical Factors Influencing Viability of Wave Energy Converters in Off-Grid Luxury Resorts and Small Utilities

Directory of Open Access Journals (Sweden)

Aksel Botne Sandberg

2016-12-01

Full Text Available This paper examines technical and non-technical factors that are critical to the viability of commercialization of wave energy converters in off-grid luxury resorts and small utilities. Critical factors are found by investigating Levelized Cost of Energy, and using the tools PESTEL and Porter’s five competitive forces. Identified factors are then applied on three business cases to investigate their impact on viability. The results show that one of the main challenges facing off-grid commercialization is the few wave energy converter units installed per location, negating the economy of scale that large wave energy farms count on to achieve competitive cost levels. In addition, factors like current cost of energy, available wave resources, distance from shore, infrastructure, supply chain logistics, and electricity demand are found to be deciding factors for viability. Despite these challenges, it is found that there are potentially viable off-grid business cases for commercialization of wave energy converters.

ENERGY CONTENT AND PROPAGATION IN TRANSVERSE SOLAR ATMOSPHERIC WAVES

Energy Technology Data Exchange (ETDEWEB)

Goossens, M.; Van Doorsselaere, T. [Centre for mathematical Plasma Astrophysics, Mathematics Department, Celestijnenlaan 200B bus 2400, B-3001 Heverlee (Belgium); Soler, R. [Solar Physics Group, Departament de Fisica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Verth, G., E-mail: tom.vandoorsselaere@wis.kuleuven.be [Solar Physics and Space Plasma Research Centre (SP2RC), School of Mathematics and Statistics, University of Sheffield, Hounsfield Road, Hicks Building, Sheffield S3 7RH (United Kingdom)

2013-05-10

Recently, a significant amount of transverse wave energy has been estimated propagating along solar atmospheric magnetic fields. However, these estimates have been made with the classic bulk Alfven wave model which assumes a homogeneous plasma. In this paper, the kinetic, magnetic, and total energy densities and the flux of energy are computed for transverse MHD waves in one-dimensional cylindrical flux tube models with a piecewise constant or continuous radial density profile. There are fundamental deviations from the properties for classic bulk Alfven waves. (1) There is no local equipartition between kinetic and magnetic energy. (2) The flux of energy and the velocity of energy transfer have, in addition to a component parallel to the magnetic field, components in the planes normal to the magnetic field. (3) The energy densities and the flux of energy vary spatially, contrary to the case of classic bulk Alfven waves. This last property has the important consequence that the energy flux computed with the well known expression for bulk Alfven waves could overestimate the real flux by a factor in the range 10-50, depending on the flux tube equilibrium properties.

Coordinated Control of Wave Energy Converters Subject to Motion Constraints

Directory of Open Access Journals (Sweden)

Liguo Wang

2016-06-01

Full Text Available In this paper, a generic coordinated control method for wave energy converters is proposed, and the constraints on motion amplitudes and the hydrodynamic interaction between converters are considered. The objective of the control problem is to maximize the energy converted from ocean waves, and this is achieved by coordinating the power take-off (PTO damping of each wave energy converter in the frequency domain in each sea state. In a case study, a wave energy farm consisting of four converters based on the concept developed by Uppsala University is studied. In the solution, motion constraints, including constraints on the amplitudes of displacement and velocity, are included. Twelve months of sea states, based on measured wave data at the Lysekil test site on the Swedish west coast, are used in the simulation to evaluate the performance of the wave energy farm using the new method. Results from the new coordinated control method and traditional control method are compared, indicating that the coordinated control of wave energy converters is an effective way to improve the energy production of wave energy farm in harmonic waves.

In-medium P-wave quarkonium from the complex lattice QCD potential

International Nuclear Information System (INIS)

Burnier, Yannis; Kaczmarek, Olaf; Rothkopf, Alexander

2016-01-01

We extend our lattice QCD potential based study http://dx.doi.org/10.1007/JHEP12(2015)101 of the in-medium properties of heavy quark bound states to P-wave bottomonium and charmonium. Similar to the behavior found in the S-wave channel their spectra show a characteristic broadening, as well as mass shifts to lower energy with increasing temperature. In contrast to the S-wave states, finite angular momentum leads to the survival of spectral peaks even at temperatures, where the continuum threshold reaches below the bound state remnant mass. We elaborate on the ensuing challenges in defining quarkonium dissolution and present estimates of melting temperatures for the spin averaged χ b and χ c states. As an application to heavy-ion collisions we further estimate the contribution of feed down to S-wave quarkonium through the P-wave states after freezeout.

In-medium P-wave quarkonium from the complex lattice QCD potential

Energy Technology Data Exchange (ETDEWEB)

Burnier, Yannis [Institute of Theoretical Physics, EPFL,CH-1015 Lausanne (Switzerland); Kaczmarek, Olaf [Fakultät für Physik, Universität Bielefeld,D-33615 Bielefeld (Germany); Rothkopf, Alexander [Institute for Theoretical Physics, Heidelberg University,Philosophenweg 16, 69120 Heidelberg (Germany)

2016-10-07

We extend our lattice QCD potential based study http://dx.doi.org/10.1007/JHEP12(2015)101 of the in-medium properties of heavy quark bound states to P-wave bottomonium and charmonium. Similar to the behavior found in the S-wave channel their spectra show a characteristic broadening, as well as mass shifts to lower energy with increasing temperature. In contrast to the S-wave states, finite angular momentum leads to the survival of spectral peaks even at temperatures, where the continuum threshold reaches below the bound state remnant mass. We elaborate on the ensuing challenges in defining quarkonium dissolution and present estimates of melting temperatures for the spin averaged χ{sub b} and χ{sub c} states. As an application to heavy-ion collisions we further estimate the contribution of feed down to S-wave quarkonium through the P-wave states after freezeout.

Wave-Particle Energy Exchange Directly Observed in a Kinetic Alfven-Branch Wave

Science.gov (United States)

Gershman, Daniel J.; F-Vinas, Adolfo; Dorelli, John C.; Boardsen, Scott A. (Inventor); Avanov, Levon A.; Bellan, Paul M.; Schwartz, Steven J.; Lavraud, Benoit; Coffey, Victoria N.; Chandler, Michael O.;

Numerical study on design for wave energy generation of a floater for energy absorption

International Nuclear Information System (INIS)

Li, Kui Ming; Parthasarathy, Nanjundan; Choi, Yoon Hwan; Lee, Yeon Won

2012-01-01

In order to design a wave energy generating system of a floater type, a 6 DOF motion technique was applied to the three Dimensional CFD analysis on a floating body and the behavior was interpreted according to the nature of the incoming waves. Waves in a tank model were generated using a single floater comparing with that of a Pelamis wave energy converter. In this paper, we focus on four variables, namely the wave height, angular velocity, diameter and length of the floater. The process was carried out in three stages and it was found that there are energy absorption differences in different parameters of wave height, length and the diameter of a floater during simulation, thus leading for the necessity of an optimal design for wave energy generation

Experimental Study on the Langlee Wave Energy Converter

DEFF Research Database (Denmark)

Pecher, Arthur; Kofoed, Jens Peter; Weisz, A.

This report presents the results of an experimental study of the wave energy converting abilities of the Langlee wave energy converter (WEC). It focused mainly on evaluating the power generating capabilities of the device, including investigations of the following issues: Scaling ratiosPTO loadingWave...... height and wave period dependencyOblique incoming waves and directional spreading of waves (3D waves)Damping platesMooring forces and fixed structure setupPitch, surge and heave motion During the study the model supplied by the client (Langlee Wave Power AS) has been heavily instrumented - up to 23...... different instruments was deployed to measure and record data. Tests were performed at scales of 1:30 and 1:20 based on the realized reference wave states....

Harnessing Alternative Energy Sources to Enhance the Design of a Wave Generator

Science.gov (United States)

Bravo, A.

2017-12-01

Wave energy has the power to replace a non-renewable source of electricity for a home near the ocean. I built a small-scale wave generator capable of producing approximately 5 volts of electricity. The generator is an array of 16 small generators, each consisting of 200 feet of copper wire, 12 magnets, and a buoy. I tested my design in the Pacific Ocean and was able to power a string of lights I had attached to the generator. While the waves in the ocean moved my buoys, my design was powered by the vertical motion of the waves. My generator was hit with significant horizontal wave motion, and I realized I wasn't taking advantage of that direction of motion. To make my generator produce more electricity, I experimented with capturing the energy of the horizontal motion of water and incorporated that into my generator design. My generator, installed in the ocean, is also exposed to sun and wind, and I am exploring the potential of solar and wind energy collection in my design to increase the electricity output. Once I have maximized my electricity output, I would like to explore scaling up my design.

Effects of Wave Energy Converter (WEC) Arrays on Wave, Current, and Sediment Circulation

Science.gov (United States)

Ruehl, K.; Roberts, J. D.; Jones, C.; Magalen, J.; James, S. C.

2012-12-01

The characterization of the physical environment and commensurate alteration of that environment due to Wave Energy Conversion (WEC) devices, or arrays of devices, must be understood to make informed device-performance predictions, specifications of hydrodynamic loads, and environmental evaluations of eco-system responses (e.g., changes to circulation patterns, sediment dynamics, and water quality). Hydrodynamic and sediment issues associated with performance of wave-energy devices will primarily be nearshore where WEC infrastructure (e.g., anchors, piles) are exposed to large forces from the surface-wave action and currents. Wave-energy devices will be subject to additional corrosion, fouling, and wear of moving parts caused by suspended sediments in the water column. The alteration of the circulation and sediment transport patterns may also alter local ecosystems through changes in benthic habitat, circulation patterns, or other environmental parameters. Sandia National Laboratories is developing tools and performing studies to quantitatively characterize the environments where WEC devices may be installed and to assess potential affects to hydrodynamics and local sediment transport. The primary tools are wave, hydrodynamic, and sediment transport models. To ensure confidence in the resulting evaluation of system-wide effects, the models are appropriately constrained and validated with measured data where available. An extension of the US EPA's EFDC code, SNL-EFDC, provides a suitable platform for modeling the necessary hydrodynamics;it has been modified to directly incorporate output from a SWAN wave model of the region. Model development and results are presented. In this work, a model is exercised for Monterey Bay, near Santa Cruz where a WEC array could be deployed. Santa Cruz is located on the northern coast of Monterey Bay, in Central California, USA. This site was selected for preliminary research due to the readily available historical hydrodynamic data

Integrated analysis of energy transfers in elastic-wave turbulence.

Science.gov (United States)

Yokoyama, Naoto; Takaoka, Masanori

2017-08-01

In elastic-wave turbulence, strong turbulence appears in small wave numbers while weak turbulence does in large wave numbers. Energy transfers in the coexistence of these turbulent states are numerically investigated in both the Fourier space and the real space. An analytical expression of a detailed energy balance reveals from which mode to which mode energy is transferred in the triad interaction. Stretching energy excited by external force is transferred nonlocally and intermittently to large wave numbers as the kinetic energy in the strong turbulence. In the weak turbulence, the resonant interactions according to the weak turbulence theory produce cascading net energy transfer to large wave numbers. Because the system's nonlinearity shows strong temporal intermittency, the energy transfers are investigated at active and moderate phases separately. The nonlocal interactions in the Fourier space are characterized by the intermittent bundles of fibrous structures in the real space.

Final Report Feasibility Study for the California Wave Energy Test Center (CalWavesm) - Volume #2 - Appendices #16-17

Energy Technology Data Exchange (ETDEWEB)

Dooher, Brendan [Pacific Gas and Electric Company, San Ramon, CA (United States). Applied Technical Services; Toman, William I. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States). Inst. of Advanced Technology and Public Policy; Davy, Doug M. [CH2M Hill Engineers, Inc., Sacramento, CA (United States); Blakslee, Samuel N. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)

2017-07-31

The California Wave Energy Test Center (CalWave) Feasibility Study project was funded over multiple phases by the Department of Energy to perform an interdisciplinary feasibility assessment to analyze the engineering, permitting, and stakeholder requirements to establish an open water, fully energetic, grid connected, wave energy test center off the coast of California for the purposes of advancing U.S. wave energy research, development, and testing capabilities. Work under this grant included wave energy resource characterization, grid impact and interconnection requirements, port infrastructure and maritime industry capability/suitability to accommodate the industry at research, demonstration and commercial scale, and macro and micro siting considerations. CalWave Phase I performed a macro-siting and down-selection process focusing on two potential test sites in California: Humboldt Bay and Vandenberg Air Force Base. This work resulted in the Vandenberg Air Force Base site being chosen as the most favorable site based on a peer reviewed criteria matrix. CalWave Phase II focused on four siting location alternatives along the Vandenberg Air Force Base coastline and culminated with a final siting down-selection. Key outcomes from this work include completion of preliminary engineering and systems integration work, a robust turnkey cost estimate, shoreside and subsea hazards assessment, storm wave analysis, lessons learned reports from several maritime disciplines, test center benchmarking as compared to existing international test sites, analysis of existing applicable environmental literature, the completion of a preliminary regulatory, permitting and licensing roadmap, robust interaction and engagement with state and federal regulatory agency personnel and local stakeholders, and the population of a Draft Federal Energy Regulatory Commission (FERC) Preliminary Application Document (PAD). Analysis of existing offshore oil and gas infrastructure was also performed

Underwater noise from a wave energy converter

DEFF Research Database (Denmark)

Tougaard, Jakob

A recent addition to the anthropogenic sources of underwater noise is offshore wave energy converters. Underwater noise was recorded from the Wavestar wave energy converter located at Hastholm, Denmark (57°7.73´N, 8°37.23´E). The Wavestar is a full-scale test and demonstration converter...... in full operation and start and stop of the converter. Median broad band (10 Hz – 20 kHz) sound pressure level (Leq) was 123 dB re. 1 Pa, irrespective of status of the wave energy converter (stopped, running or starting/stopping). The most pronounced peak in the third-octave spectrum was in the 160 Hz...... significant noise above ambient could be detected above the 250 Hz band. The absolute increase in noise above ambient was very small. L50 third-octave levels in the four bands with the converter running were thus only 1-2 dB above ambient L50 levels. The noise recorded 25 m from the wave energy converter...

Buoy and Generator Interaction with Ocean Waves: Studies of a Wave Energy Conversion System

Energy Technology Data Exchange (ETDEWEB)

Lindroth, Simon

2011-07-01

On March 13th, 2006, the Div. of Electricity at Uppsala Univ. deployed its first wave energy converter, L1, in the ocean southwest of Lysekil. L1 consisted of a buoy at the surface, connected through a line to a linear generator on the seabed. Since the deployment, continuous investigations of how L1 works in the waves have been conducted, and several additional wave energy converters have been deployed. This thesis is based on ten publications, which focus on different aspects of the interaction between wave, buoy, and generator. In order to evaluate different measurement systems, the motion of the buoy was measured optically and using accelerometers, and compared to measurements of the motion of the movable part of the generator - the translator. These measurements were found to correlate well. Simulations of buoy and translator motion were found to match the measured values. The variation of performance of L1 with changing water levels, wave heights, and spectral shapes was also investigated. Performance is here defined as the ratio of absorbed power to incoming power. It was found that the performance decreases for large wave heights. This is in accordance with the theoretical predictions, since the area for which the stator and the translator overlap decreases for large translator motions. Shifting water levels were predicted to have the same effect, but this could not be seen as clearly. The width of the wave energy spectrum has been proposed by some as a factor that also affects the performance of a wave energy converter, for a set wave height and period. Therefore the relation between performance and several different parameters for spectral width was investigated. It was found that some of the parameters were in fact correlated to performance, but that the correlation was not very strong. As a background on ocean measurements in wave energy, a thorough literature review was conducted. It turns out that the Lysekil project is one of quite few projects that

Proceedings of the Hydrokinetic and Wave Energy Technologies Technical and Environmental Issues Workshop

Energy Technology Data Exchange (ETDEWEB)

None

2006-03-01

Renewable energy technologies offer the promise of non-polluting alternatives to fossil and nuclear-fueled power plants to meet growing demand for electrical energy. Two emerging categories of renewable energy technologies, hydrokinetic and wave energy conversion devices, offer ways to tap the energy of moving water without impoundment (dams) or diversion required by many conventional hydroelectric facilities. These technologies include devices designed for deployment in natural streams, tidal estuaries, ocean currents, and constructed waterways, as well as devices designed to capture the energy of ocean waves. On October 26-28, 2005, 54 representatives from government, non-governmental organizations, and private business met to (1) identify the varieties of hydrokinetic energy and wave technology devices, their stages of development, and the projected cost to bring each to market; (2) identify where these technologies can best operate; (3) identify the potential environmental issues associated with these technologies and possible mitigation measures; (4) develop a list of research needs and/or practical solutions to address unresolved environmental issues. These workshop proceedings include detailed summaries of the 24 presentations made and the discussions that followed.

S-matrix to potential inversion of low-energy. alpha. - sup 12 C phase shifts

Energy Technology Data Exchange (ETDEWEB)

Cooper, S.G.; Mackintosh, R.S. (Open Univ., Milton Keynes (UK). Dept. of Physics)

1990-10-22

The IP S-matrix to potential inversion procedure is applied to phase shifts for selected partial waves over a range of energies below the inelastic threshold for {alpha}-{sup 12}C scattering. The phase shifts were determined by Plaga et al. Potentials found by Buck and Rubio to fit the low-energy alpha cluster resonances need only an increased attraction in the surface to accurately reproduce the phase-shift behaviour. Substantial differences between the potentials for odd and even partial waves are necessary. The surface tail of the potential is postulated to be a threshold effect. (orig.).

The Draukie's Tale: Origin Myth for Wave Energy

DEFF Research Database (Denmark)

Watts, Laura

2017-01-01

Poem based on ethnographic research with people and places around the European Marine Energy Centre, the world's longest running test site for wave and tide energy, Orkney islands, Scotland.......Poem based on ethnographic research with people and places around the European Marine Energy Centre, the world's longest running test site for wave and tide energy, Orkney islands, Scotland....

Wave energy transmission apparatus for high-temperature environments

Science.gov (United States)

Buckley, John D. (Inventor); Edwards, William C. (Inventor); Kelliher, Warren C. (Inventor); Carlberg, Ingrid A. (Inventor)

2010-01-01

A wave energy transmission apparatus has a conduit made from a refractory oxide. A transparent, refractory ceramic window is coupled to the conduit. Wave energy passing through the window enters the conduit.

Conceptual Design of Wave Plane

DEFF Research Database (Denmark)

Frigaard, Peter; Trewers, Andrew; Kofoed, Jens Peter

The Wave Plane is a patented Wave Energy device of the overtopping type, designed to capture potential as well as kinetic energy. This is as such different to other overtopping devices, who usually only focus on potential energy. If Wave Plane A/S can deliver the turbine technology to utilize both...

Wave

DEFF Research Database (Denmark)

Ibsen, Lars Bo

2008-01-01

Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many...... times smaller it remains very high. For example, whilst there is enough potential wave power off the UK to supply the electricity demands several times over, the economically recoverable resource for the UK is estimated at 25% of current demand; a lot less, but a very substantial amount nonetheless....

Advanced computational simulations of water waves interacting with wave energy converters

Science.gov (United States)

Pathak, Ashish; Freniere, Cole; Raessi, Mehdi

2017-03-01

Wave energy converter (WEC) devices harness the renewable ocean wave energy and convert it into useful forms of energy, e.g. mechanical or electrical. This paper presents an advanced 3D computational framework to study the interaction between water waves and WEC devices. The computational tool solves the full Navier-Stokes equations and considers all important effects impacting the device performance. To enable large-scale simulations in fast turnaround times, the computational solver was developed in an MPI parallel framework. A fast multigrid preconditioned solver is introduced to solve the computationally expensive pressure Poisson equation. The computational solver was applied to two surface-piercing WEC geometries: bottom-hinged cylinder and flap. Their numerically simulated response was validated against experimental data. Additional simulations were conducted to investigate the applicability of Froude scaling in predicting full-scale WEC response from the model experiments.

Molecular wave function and effective adiabatic potentials calculated by extended multi-configuration time-dependent Hartree-Fock method

Energy Technology Data Exchange (ETDEWEB)

Kato, Tsuyoshi; Ide, Yoshihiro; Yamanouchi, Kaoru [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1, Hongo Bunkyo-ku, Tokyo, 113-0033 (Japan)

2015-12-31

We first calculate the ground-state molecular wave function of 1D model H{sub 2} molecule by solving the coupled equations of motion formulated in the extended multi-configuration time-dependent Hartree-Fock (MCTDHF) method by the imaginary time propagation. From the comparisons with the results obtained by the Born-Huang (BH) expansion method as well as with the exact wave function, we observe that the memory size required in the extended MCTDHF method is about two orders of magnitude smaller than in the BH expansion method to achieve the same accuracy for the total energy. Second, in order to provide a theoretical means to understand dynamical behavior of the wave function, we propose to define effective adiabatic potential functions and compare them with the conventional adiabatic electronic potentials, although the notion of the adiabatic potentials is not used in the extended MCTDHF approach. From the comparison, we conclude that by calculating the effective potentials we may be able to predict the energy differences among electronic states even for a time-dependent system, e.g., time-dependent excitation energies, which would be difficult to be estimated within the BH expansion approach.

A comparative analysis of the environmental impacts of a Pelamis Wave Energy device with existing off shore developments and installations.

OpenAIRE

Quinn, Eoghan

2011-01-01

Scotland is currently at the forefront of development and expansion of wave energy, especially with recent renewable energy targets. Research and development has increased greatly off the Scottish coastline. Various adjectives can be used to describe wave energy’s creative potential in helping to achieve Scotland’s energy goals. Put simply however the production of wave energy appears to have all the ingredients for success; it is benign, the visual impacts minimal and its energy is reliable,...

Scattering at zero energy for attractive homogeneous potentials

DEFF Research Database (Denmark)

Derezinski, Jan; Skibsted, Erik

2009-01-01

We compute up to a compact term the zero-energy scattering matrix for a class of potentials asymptotically behaving as −γ|x|−μ with 0 < μ < 2 and γ > 0. It turns out to be the propagator for the wave equation on the sphere at time ....

Hydrodynamic analysis and shape optimization for vertical axisymmetric wave energy converters

Science.gov (United States)

Zhang, Wan-chao; Liu, Heng-xu; Zhang, Liang; Zhang, Xue-wei

2016-12-01

The absorber is known to be vertical axisymmetric for a single-point wave energy converter (WEC). The shape of the wetted surface usually has a great influence on the absorber's hydrodynamic characteristics which are closely linked with the wave power conversion ability. For complex wetted surface, the hydrodynamic coefficients have been predicted traditionally by hydrodynamic software based on the BEM. However, for a systematic study of various parameters and geometries, they are too multifarious to generate so many models and data grids. This paper examines a semi-analytical method of decomposing the complex axisymmetric boundary into several ring-shaped and stepped surfaces based on the boundary discretization method (BDM) which overcomes the previous difficulties. In such case, by using the linear wave theory based on eigenfunction expansion matching method, the expressions of velocity potential in each domain, the added mass, radiation damping and wave excitation forces of the oscillating absorbers are obtained. The good astringency of the hydrodynamic coefficients and wave forces are obtained for various geometries when the discrete number reaches a certain value. The captured wave power for a same given draught and displacement for various geometries are calculated and compared. Numerical results show that the geometrical shape has great effect on the wave conversion performance of the absorber. For absorbers with the same outer radius and draught or displacement, the cylindrical type shows fantastic wave energy conversion ability at some given frequencies, while in the random sea wave, the parabolic and conical ones have better stabilization and applicability in wave power conversion.

Conversion of the energy of a high-current REB into electromagnetic wave energy

International Nuclear Information System (INIS)

Kurilko, V.I.; Kharchenko, I.F.

2000-01-01

Results are presented from a theoretical investigation and quantitative analysis of the physical processes that govern the efficiency of a coaxial device aimed at converting the energy of a relativistic electron beam into the energy of a TEM wave (a wave in a circular cylindrical coaxial waveguide). The key diffractional problem is solved exactly using a simplified theoretical model, which makes it possible to understand the mechanisms for the formation of a TEM wave and determine how the beam parameters and the design parameters of the converter affect the relative fractions of the kinetic energy of a relativistic electron beam and the energy of its own magnetic and electric fields that are transferred into the energy of the TEM wave field. The results obtained are analyzed quantitatively, and prospects for further theoretical and experimental research in this area are outlined

A framework for assessing the uncertainty in wave energy delivery to targeted subsurface formations

Science.gov (United States)

Karve, Pranav M.; Kallivokas, Loukas F.; Manuel, Lance

2016-02-01

Stress wave stimulation of geological formations has potential applications in petroleum engineering, hydro-geology, and environmental engineering. The stimulation can be applied using wave sources whose spatio-temporal characteristics are designed to focus the emitted wave energy into the target region. Typically, the design process involves numerical simulations of the underlying wave physics, and assumes a perfect knowledge of the material properties and the overall geometry of the geostructure. In practice, however, precise knowledge of the properties of the geological formations is elusive, and quantification of the reliability of a deterministic approach is crucial for evaluating the technical and economical feasibility of the design. In this article, we discuss a methodology that could be used to quantify the uncertainty in the wave energy delivery. We formulate the wave propagation problem for a two-dimensional, layered, isotropic, elastic solid truncated using hybrid perfectly-matched-layers (PMLs), and containing a target elastic or poroelastic inclusion. We define a wave motion metric to quantify the amount of the delivered wave energy. We, then, treat the material properties of the layers as random variables, and perform a first-order uncertainty analysis of the formation to compute the probabilities of failure to achieve threshold values of the motion metric. We illustrate the uncertainty quantification procedure using synthetic data.

Direct Quantum Dynamics Using Grid-Based Wave Function Propagation and Machine-Learned Potential Energy Surfaces.

Science.gov (United States)

Richings, Gareth W; Habershon, Scott

2017-09-12

We describe a method for performing nuclear quantum dynamics calculations using standard, grid-based algorithms, including the multiconfiguration time-dependent Hartree (MCTDH) method, where the potential energy surface (PES) is calculated "on-the-fly". The method of Gaussian process regression (GPR) is used to construct a global representation of the PES using values of the energy at points distributed in molecular configuration space during the course of the wavepacket propagation. We demonstrate this direct dynamics approach for both an analytical PES function describing 3-dimensional proton transfer dynamics in malonaldehyde and for 2- and 6-dimensional quantum dynamics simulations of proton transfer in salicylaldimine. In the case of salicylaldimine we also perform calculations in which the PES is constructed using Hartree-Fock calculations through an interface to an ab initio electronic structure code. In all cases, the results of the quantum dynamics simulations are in excellent agreement with previous simulations of both systems yet do not require prior fitting of a PES at any stage. Our approach (implemented in a development version of the Quantics package) opens a route to performing accurate quantum dynamics simulations via wave function propagation of many-dimensional molecular systems in a direct and efficient manner.

A performance study on a direct drive hydro turbine for wave energy converter

International Nuclear Information System (INIS)

Choi, Young Do; Kim, Chang Goo; Kim, You Taek; Lee, Young Ho; Song, Jung Il

2010-01-01

Clean and renewable energy technologies using ocean energy give us non-polluting alternatives to fossil-fueled power plants as a countermeasure against global warming and growing demand for electrical energy. Among the ocean energy resources, wave power takes a growing interest because of its enormous amount of potential energy in the world. Therefore, various types of wave power systems to capture the energy of ocean waves have been developed. However, a suitable turbine type is not yet normalized because of relatively low efficiency of the turbine systems. The purpose of this study is to investigate the performance of a newly developed direct drive hydro turbine (DDT), which will be built in a caisson for a wave power plant. Experiment and CFD analysis are conducted to clarify the turbine performance and internal flow characteristics. The results show that the DDT obtains fairly good turbine efficiency in cases with and without wave conditions. Most of the output power is generated at the runner passage of Stage 2. Relatively larger amount of the decreased tangential velocity at Stage 2 produces more angular momentum than that at Stage 1 and thus, the larger angular momentum at the Stage 2 makes a greater contribution to the generation of total output power in comparison with that at Stage 1. Large vortex existing in the upper-left region of the runner passage forms a large recirculation region in the runner passage, and the recirculating flow consumes the output power at Region 2

A performance study on a direct drive hydro turbine for wave energy converter

Energy Technology Data Exchange (ETDEWEB)

Choi, Young Do [Mokpo National University, Muan (Korea, Republic of); Kim, Chang Goo; Kim, You Taek; Lee, Young Ho [Korea Maritime University, Busan (Korea, Republic of); Song, Jung Il [Changwon National University, Changwon (Korea, Republic of)

2010-11-15

Clean and renewable energy technologies using ocean energy give us non-polluting alternatives to fossil-fueled power plants as a countermeasure against global warming and growing demand for electrical energy. Among the ocean energy resources, wave power takes a growing interest because of its enormous amount of potential energy in the world. Therefore, various types of wave power systems to capture the energy of ocean waves have been developed. However, a suitable turbine type is not yet normalized because of relatively low efficiency of the turbine systems. The purpose of this study is to investigate the performance of a newly developed direct drive hydro turbine (DDT), which will be built in a caisson for a wave power plant. Experiment and CFD analysis are conducted to clarify the turbine performance and internal flow characteristics. The results show that the DDT obtains fairly good turbine efficiency in cases with and without wave conditions. Most of the output power is generated at the runner passage of Stage 2. Relatively larger amount of the decreased tangential velocity at Stage 2 produces more angular momentum than that at Stage 1 and thus, the larger angular momentum at the Stage 2 makes a greater contribution to the generation of total output power in comparison with that at Stage 1. Large vortex existing in the upper-left region of the runner passage forms a large recirculation region in the runner passage, and the recirculating flow consumes the output power at Region 2

Low energy consumption vortex wave flow membrane bioreactor.

Science.gov (United States)

Wang, Zhiqiang; Dong, Weilong; Hu, Xiaohong; Sun, Tianyu; Wang, Tao; Sun, Youshan

2017-11-01

In order to reduce the energy consumption and membrane fouling of the conventional membrane bioreactor (MBR), a kind of low energy consumption vortex wave flow MBR was exploited based on the combination of biofilm process and membrane filtration process, as well as the vortex wave flow technique. The experimental results showed that the vortex wave flow state in the membrane module could be formed when the Reynolds number (Re) of liquid was adjusted between 450 and 1,050, and the membrane flux declined more slowly in the vortex wave flow state than those in the laminar flow state and turbulent flow state. The MBR system was used to treat domestic wastewater under the condition of vortex wave flow state for 30 days. The results showed that the removal efficiency for CODcr and NH 3 -N was 82% and 98% respectively, and the permeate quality met the requirement of 'Water quality standard for urban miscellaneous water consumption (GB/T 18920-2002)'. Analysis of the energy consumption of the MBR showed that the average energy consumption was 1.90 ± 0.55 kWh/m 3 (permeate), which was only two thirds of conventional MBR energy consumption.

Introduction Of Wavestar Wave Energy Converters At The Danish Offshore Wind Power Plant Horns Rev 2

DEFF Research Database (Denmark)

Marquis, L.; Kramer, Morten; Kringelum, J.

is to be connected to a wind turbine at the DONG Energy owned wind power plant Horns Rev 2 placed off the western coast of Denmark. The plant delivers its energy production to a transformer station owned by Energinet.dk. Energinet.dk has the obligation to ensure that power is transmitted to the Danish consumers...... with this combination. This can increase the value of the produced power from future wind/wave plants. Further potential synergies of combining wind and wave energy in the same area include increased energy production from the available area and sharing of infrastructure costs as well as O&M facilities. In a future....... If Executed the project will be the first one in the world where wind and wave power are combined at full scale. The goal of the project is to evaluate the opportunities of combining wind and wave energy production on a commercial scale and to demonstrate the reduction of energy fluctuations...

Stakeholder requirements for commercially successful wave energy converter farms

Energy Technology Data Exchange (ETDEWEB)

Babarit, Aurélien; Bull, Diana; Dykes, Katherine; Malins, Robert; Nielsen, Kim; Costello, Ronan; Roberts, Jesse; Bittencourt Ferreira, Claudio; Kennedy, Ben; Weber, Jochem

2017-12-01

In this study, systems engineering techniques are applied to wave energy to identify and specify stakeholders' requirements for a commercially successful wave energy farm. The focus is on the continental scale utility market. Lifecycle stages and stakeholders are identified. Stakeholders' needs across the whole lifecycle of the wave energy farm are analyzed. A list of 33 stakeholder requirements are identified and specified. This list of requirements should serve as components of a technology performance level metric that could be used by investors and funding agencies to make informed decisions when allocating resources. It is hoped that the technology performance level metric will accelerate wave energy conversion technology convergence.

Dispersion relation and Landau damping of waves in high-energy density plasmas

International Nuclear Information System (INIS)

Zhu Jun; Ji Peiyong

2012-01-01

We present a theoretical investigation on the propagation of electromagnetic waves and electron plasma waves in high energy density plasmas using the covariant Wigner function approach. Based on the covariant Wigner function and Dirac equation, a relativistic quantum kinetic model is established to describe the physical processes in high-energy density plasmas. With the zero-temperature Fermi–Dirac distribution, the dispersion relation and Landau damping of waves containing the relativistic quantum corrected terms are derived. The relativistic quantum corrections to the dispersion relation and Landau damping are analyzed by comparing our results with those obtained in classical and non-relativistic quantum plasmas. We provide a detailed discussion on the Landau damping obtained in classical plasmas, non-relativistic Fermi plasmas and relativistic Fermi plasmas. The contributions of the Bohm potential, the Fermi statistics pressure and relativistic effects to the dispersion relation and Landau damping of waves are quantitatively calculated with real plasma parameters. (paper)

Preliminary Load Estimations for DEXA Wave Energy Device - Hanstholm, Denmark

DEFF Research Database (Denmark)

Kofoed, Jens Peter

by DEXA Wave Energy ApS, in regular and irregular wave states, as described in Assessment of Wave Energy Devices. Best Practice as used in Denmark (Frigaard et al., 2008). The length scale of the model was 1:20 compared to a full scale device suitable fro the Danish part of the North Sea, according...... to DEXA Wave Energy ApS. The tests were carried out at Dept. of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The displacement and force applied to a power take off system, provided by DEXA Wave Energy ApS, were measured and used for calculation of power available...... to the power take-off....

Numerical study of hydrodynamic behavior and conversion efficiency of a two-buoy wave energy converter

Science.gov (United States)

Yang, Cen; Zhang, Yong-liang

2018-04-01

In this paper we propose a two-buoy wave energy converter composed of a heaving semi-submerged cylindrical buoy, a fixed submerged cylindrical buoy and a power take-off (PTO) system, and investigate the effect of the fixed submerged buoy on the hydrodynamics of the heaving semi-submerged buoy based on the three-dimensional potential theory. And the dynamic response of the semi-submerged buoy and the wave energy conversion efficiency of the converter are analyzed. The difference of the hydrodynamics and the wave energy conversion efficiency of a semi-submerged buoy converter with and without a fixed submerged buoy is discussed. It is revealed that the influence of the fixed submerged buoy on the exciting wave force, the added mass, the radiation damping coefficient and the wave energy conversion efficiency can be significant with a considerable variation, depending on the vertical distance between the heaving semi-submerged buoy and the fixed submerged buoy, the diameter ratio of the fixed submerged buoy to the heaving semi-submerged buoy and the water depth.

Quantifying the Benefits of Combining Offshore Wind and Wave Energy

Science.gov (United States)

Stoutenburg, E.; Jacobson, M. Z.

2009-12-01

For many locations the offshore wind resource and the wave energy resource are collocated, which suggests a natural synergy if both technologies are combined into one offshore marine renewable energy plant. Initial meteorological assessments of the western coast of the United States suggest only a weak correlation in power levels of wind and wave energy at any given hour associated with the large ocean basin wave dynamics and storm systems of the North Pacific. This finding indicates that combining the two power sources could reduce the variability in electric power output from a combined wind and wave offshore plant. A combined plant is modeled with offshore wind turbines and Pelamis wave energy converters with wind and wave data from meteorological buoys operated by the US National Buoy Data Center off the coast of California, Oregon, and Washington. This study will present results of quantifying the benefits of combining wind and wave energy for the electrical power system to facilitate increased renewable energy penetration to support reductions in greenhouse gas emissions, and air and water pollution associated with conventional fossil fuel power plants.

IMPORTANCE OF MANGROVE TO REDUCE THE TSUNAMI WAVE ENERGY

Directory of Open Access Journals (Sweden)

Anastasia Neni Candra Purnamasari

2017-09-01

Full Text Available Mangrove has a very important role to reduce the tsunami wave energy. It is shown that the coastal areas have no vegetation or in this case will have an impact Mangrove forests greater damage due to tsunami waves than the coastal areas of vegetation. The purpose of the Term Paper is proved the importance of Mangrove to reduce the tsunami wave energy by comparing the various methods that have been observed in some case studies on the impact of the tsunami that occurred in several Asian countries in 2004 and case studies on ocean waves on the Gulf coast of south Florida. Based on the research results that could dampen Mangrove Tsunami wave energy. Tsunami wave energy can be reduced by several factors, namely mangrove species, tree size, vast mangrove forest, nature tree structure, and the size limit Mangrove forest (as far as how much of the ocean to the surface.

A Joint Evaluation of the Wind and Wave Energy Resources Close to the Greek Islands

Directory of Open Access Journals (Sweden)

Daniel Ganea

2017-06-01

Full Text Available The objective of this work is to analyze the wind and wave energy potential in the proximity of the Greek islands. Thus, by evaluating the synergy between wind and waves, a more comprehensive picture of the renewable energy resources in the target area is provided. In this study, two different data sources are considered. The first data set is provided by the European Centre for Medium-Range Weather Forecasts (ECMWF through the ERA-Interim project and covers an 11-year period, while the second data set is Archiving, Validation and Interpretation of Satellite Oceanographic data (AVISO and covers six years of information. Using these data, parameters such as wind speed, significant wave height (SWH and mean wave period (MWP are analyzed. The following marine areas are targeted: Ionian Sea, Aegean Sea, Sea of Crete, Libyan Sea and Levantine Sea, near the coastal environment of the Greek islands. Initially, 26 reference points were considered. For a more detailed analysis, the number of reference points was narrowed down to 10 that were considered more relevant. Since in the island environments the resources are in general rather limited, the proposed work provides some outcomes concerning the wind and wave energy potential and the synergy between these two natural resources in the vicinity of the Greek islands. From the analysis performed, it can be noticed that the most energetic wind conditions are encountered west of Cios Island, followed by the regions east of Tinos and northeast of Crete. In these locations, the annual average values of the wind power density (Pwind are in the range of 286–298.6 W/m2. Regarding the wave power density (Pwave, the most energetic locations can be found in the vicinity of Crete, north, south and southeast of the island. There, the wave energy potential is in the range of 2.88–2.99 kW/m.

Second generation wave energy device - the clam concept

Energy Technology Data Exchange (ETDEWEB)

Bellamy, N.W.

1981-01-01

A device concept is presented which has arisen from a system approach adopted by a research group with considerable experience in the discipline of wave energy. The Clam, which can be classified as a spine-based pneumatic terminator, is deemed to be a second generation wave energy device in that it tries to utilize system components already identified as attractive, while at the same time avoiding known problem areas. A working model of this wave power device at an engineering scale is discussed for trials in real waves. 3 refs.

Wave heating and the U.S. magnetic fusion energy program

International Nuclear Information System (INIS)

Staten, H.S.

1985-01-01

The U.S. Government's support of the fusion program is predicated upon the long-term need for the fusion option in our energy future, as well as the near-term benefits associated with developments on the frontier of science and high technology. As a long-term energy option, magnetic fusion energy has the potential to provide an inexpensive, vast, and secure fuel reserve, to be environmentally clean and safe. It has many potential uses, which include production of central station electricity, fuel for fission reactors, synthetic fuels, and process heat for such applications as desalination of sea water. This paper presents an overview of the U.S. Government program for magnetic fusion energy. The goal and objectives of the U.S. program are reviewed followed by a summary of plasma experiments presently under way and the application of wave heating to these experiments

Design and analysis of tubular permanent magnet linear generator for small-scale wave energy converter

Science.gov (United States)

Kim, Jeong-Man; Koo, Min-Mo; Jeong, Jae-Hoon; Hong, Keyyong; Cho, Il-Hyoung; Choi, Jang-Young

2017-05-01

This paper reports the design and analysis of a tubular permanent magnet linear generator (TPMLG) for a small-scale wave-energy converter. The analytical field computation is performed by applying a magnetic vector potential and a 2-D analytical model to determine design parameters. Based on analytical solutions, parametric analysis is performed to meet the design specifications of a wave-energy converter (WEC). Then, 2-D FEA is employed to validate the analytical method. Finally, the experimental result confirms the predictions of the analytical and finite element analysis (FEA) methods under regular and irregular wave conditions.

Assessment of tidal and wave energy conversion technologies in Canada

International Nuclear Information System (INIS)

2009-01-01

This paper presented an attractive option to help meet Canada's future energy needs, notably the vast and energetic Atlantic, Pacific and Arctic coastal waters which make ocean renewable energy, particularly tidal in-stream energy conversion (TISEC) and wave energy conversion (WEC). There is much uncertainty regarding the possible environmental impacts associated with their deployment and operation. In support of commercial development of the industry, a review of scientific knowledge was needed for the development of policy and regulations consistent with Canada's conservation and sustainability priorities. In April 2009, Fisheries and Oceans Canada (DFO) hosted a two-day national science advisory process meeting in order to determine the current state of knowledge on the environmental impacts of tidal and wave energy conversion technologies and their application in the Canadian context based on published reports. Potential mitigation measures were identified and the feasibility of developing a relevant Canadian statement of practice was determined. This report presented an assessment and analysis of wave power, including the impacts on physical processes; impacts on habitat characteristics; impacts on water quality; impacts of noise and vibrations; impacts of electromagnetic fields; impacts of physical encounters; cumulative impacts; and mitigation measures. It was concluded that there is a recognized need to develop and maintain national and regional georeferenced, interoperable, standards-based databases that enable access by governments, developers, academics, non-governmental organizations and the general public. 1 ref., 1 fig.

SSG wave energy converter. Design, reliability and hydraulic performance of an innovative overtopping device

Energy Technology Data Exchange (ETDEWEB)

Margheritini, L.; Frigaard, P. [Department of Civil Engineering, Aalborg University. Sohngaardsholmsvej 57, DK-9000 Aalborg (Denmark); Vicinanza, D. [Department of Civil Engineering - CIRIAM, Seconda Universita di Napoli. Via Roma 29, 81031 Aversa (Caserta) (Italy)

2009-05-15

The SSG (Sea Slot-cone Generator) is a wave energy converter of the overtopping type. The structure consists of a number of reservoirs one on the top of each other above the mean water level in which the water of incoming waves is stored temporary. In each reservoir, expressively designed low head hydro-turbines are converting the potential energy of the stored water into power. A key to success for the SSG will be the low cost of the structure and its robustness. The construction of the pilot plant is scheduled and this paper aims to describe the concept of the SSG wave energy converter and the studies behind the process that leads to its construction. The pilot plant is an on-shore full-scale module in 3 levels with an expected power production of 320 MWh/y in the North Sea. Location, wave climate and laboratory tests' results will be used here to describe the pilot plant and its characteristics. (author)

Short-Term Wave Forecasting with AR models in Real-Time Optimal Control of Wave Energy Converters

OpenAIRE

Fusco, Francesco; Ringwood, John

2010-01-01

Time domain control of wave energy converters requires knowledge of future incident wave elevation in order to approach conditions for optimal energy extraction. Autoregressive models revealed to be a promising approach to the prediction of future values of the wave elevation only from its past history. Results on real wave observations from different ocean locations show that AR models allow to achieve very good predictions for more than one wave period in the future if ...

Designing and Testing Composite Energy Storage Systems for Regulating the Outputs of Linear Wave Energy Converters

Directory of Open Access Journals (Sweden)

Zanxiang Nie

2017-01-01

Full Text Available Linear wave energy converters generate intrinsically intermittent power with variable frequency and amplitude. A composite energy storage system consisting of batteries and super capacitors has been developed and controlled by buck-boost converters. The purpose of the composite energy storage system is to handle the fluctuations and intermittent characteristics of the renewable source, and hence provide a steady output power. Linear wave energy converters working in conjunction with a system composed of various energy storage devices, is considered as a microsystem, which can function in a stand-alone or a grid connected mode. Simulation results have shown that by applying a boost H-bridge and a composite energy storage system more power could be extracted from linear wave energy converters. Simulation results have shown that the super capacitors charge and discharge often to handle the frequent power fluctuations, and the batteries charge and discharge slowly for handling the intermittent power of wave energy converters. Hardware systems have been constructed to control the linear wave energy converter and the composite energy storage system. The performance of the composite energy storage system has been verified in experiments by using electronics-based wave energy emulators.

The energy density of a Landau damped plasma wave

NARCIS (Netherlands)

Best, R. W. B.

1999-01-01

In this paper some theories about the energy of a Landau damped plasma wave are discussed and new initial conditions are proposed. Analysis of a wave packet, rather than an infinite wave, gives a clear picture of the energy transport from field to particles. Initial conditions are found which excite

Exploring Marine Energy Potential in the UK Using a Whole Systems Modelling Approach

Directory of Open Access Journals (Sweden)

Anna Stegman

2017-08-01

Full Text Available The key market drivers for marine energy are to reduce carbon emissions, and improve the security and sustainability of supply. There are other technologies that also meet these requirements, and therefore the marine energy market is dependent on the technology being cost effective, and competitive. The potential UK wave and tidal stream energy market is assessed using ETI’s energy systems modelling environment (ESME which uses a multi-vector approach including energy generation, demand, heat, transport, and infrastructure. This is used to identify scenarios where wave and tidal energy form part of the least-cost energy system for the UK by 2050, and will assess what Levelised Cost of Energy (LCOE reductions are required to improve the commercialization rate. The results indicate that an installed capacity of 4.9 GW of wave and 2.5 GW of tidal stream could be deployed by 2050 if the LCOE is within 4.5 and 7 p/kWh for each respective technology. If there is a step reduction to the LCOE of wave energy, however, a similar capacity of 5 GW could be deployed by 2050 at a LCOE of 11 p/kWh.

Key features of wave energy.

Science.gov (United States)

Rainey, R C T

2012-01-28

For a weak point source or dipole, or a small body operating as either, we show that the power from a wave energy converter (WEC) is the product of the particle velocity in the waves, and the wave force (suitably defined). There is a thus a strong analogy with a wind or tidal turbine, where the power is the product of the fluid velocity through the turbine, and the force on it. As a first approximation, the cost of a structure is controlled by the force it has to carry, which governs its strength, and the distance it has to be carried, which governs its size. Thus, WECs are at a disadvantage compared with wind and tidal turbines because the fluid velocities are lower, and hence the forces are higher. On the other hand, the distances involved are lower. As with turbines, the implication is also that a WEC must make the most of its force-carrying ability-ideally, to carry its maximum force all the time, the '100% sweating WEC'. It must be able to limit the wave force on it in larger waves, ultimately becoming near-transparent to them in the survival condition-just like a turbine in extreme conditions, which can stop and feather its blades. A turbine of any force rating can achieve its maximum force in low wind speeds, if its diameter is sufficiently large. This is not possible with a simple monopole or dipole WEC, however, because of the 'nλ/2π' capture width limits. To achieve reasonable 'sweating' in typical wave climates, the force is limited to about 1 MN for a monopole device, or 2 MN for a dipole. The conclusion is that the future of wave energy is in devices that are not simple monopoles or dipoles, but multi-body devices or other shapes equivalent to arrays.

Development of the Wave Energy Converter

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter; Sørensen, Hans Christian

2000-01-01

The development of the wave energy converter Wave Dragon (WD) is presented. The WD is based on the overtopping principle. Initially a description of the WD is given. Then the development over time in terms of the various research and development projects working with the concept is described. Thi...

Wave Tank Testing and Model Validation of an Autonomous Wave Energy Converter

Directory of Open Access Journals (Sweden)

Bret Bosma

2015-08-01

Full Text Available A key component in bringing ocean wave energy converters from concept to commercialization is the building and testing of scaled prototypes to provide model validation. A one quarter scale prototype of an autonomous two body heaving point absorber was modeled, built, and tested for this work. Wave tank testing results are compared with two hydrodynamic and system models—implemented in both ANSYS AQWA and MATLAB/Simulink—and show model validation over certain regions of operation. This work will serve as a guide for future developers of wave energy converter devices, providing insight in taking their design from concept to prototype stage.

Nonlinear Passive Control of a Wave Energy Converter Subject to Constraints in Irregular Waves

Directory of Open Access Journals (Sweden)

Liguo Wang

2015-06-01

Full Text Available This paper investigates a passive control method of a point absorbing wave energy converter by considering the displacement and velocity constraints under irregular waves in the time domain. A linear generator is used as a power take-off unit, and the equivalent damping force is optimized to improve the power production of the wave energy converter. The results from nonlinear and linear passive control methods are compared, and indicate that the nonlinear passive control method leads to the excitation force in phase with the velocity of the converter that can significantly improve the energy production of the converter.

Energy-Dependent microscopic optical potential for p+{sup 9}Be elastic scattering

Energy Technology Data Exchange (ETDEWEB)

Maridi, H. M., E-mail: h.maridi@gmail.com [Physics Department, Faculty of Science, Cairo University, Giza 12613 (Egypt); Physics Department, Faculty of Applied Science, Taiz University, Taiz (Yemen); Farag, M. Y. H., E-mail: yehiafarag@cu.edu.eg; Esmael, E. H. [Physics Department, Faculty of Applied Science, Taiz University, Taiz (Yemen)

2016-06-10

The p+{sup 9}Be elastic scattering at an energy range up to 200 MeV/nucleon is analyzed using the single-folding model. The density- and isospin-dependent M3Y-Paris nucleon-nucleon (NN) interaction is used for the real part and the NN-scattering amplitude of the high-energy approximation for the imaginary one. The analysis reveals that the cross-section data are reproduced well at energies up to 100 MeV/nucleon by use of the partial-wave expansion. For higher energies, the eikonal approximation give results better than the partial-wave expansion calculations. The volume integrals of the optical-potential parts have systematic energy dependencies, and they are parameterized in empirical formulas.

Energy from the waves

CERN Document Server

Ross, D

2012-01-01

Revised and substantially expanded to include the latest developments in the field, the second edition of this popular book provides a concise, non-technical account of the historical background and current research and development in the field of wave energy and its planned utilisation. It explains in simple terms the technology involved and describes the new inventions, devices and discoveries which led wave energy to be regarded as a significant future source of alternative power. The author recounts the major events leading up to today's development; the roles played by the principal characters involved, inventors, engineers and politicians and the inevitable struggle which all pioneers must face. The book concludes by discussing the environmental implications, the political conflicts and the problems which lie ahead. Also included, is a useful glossary of terms and a selected bibliography of important technical reports and further sources of information.

Dissipation of Wave Energy by Cohesive Sediments

National Research Council Canada - National Science Library

Kaihatu, James M; Sheremet, Alexandru

2004-01-01

Wave energy dissipation by bottom muds is studied. A dissipation mechanism which contains explicit expressions of wavenumber modification due to a viscous bottom fluid is incorporated into a nonlinear wave shoaling model...

Analytical and computational modelling for wave energy systems: the example of oscillating wave surge converters

Science.gov (United States)

Dias, Frédéric; Renzi, Emiliano; Gallagher, Sarah; Sarkar, Dripta; Wei, Yanji; Abadie, Thomas; Cummins, Cathal; Rafiee, Ashkan

2017-08-01

The development of new wave energy converters has shed light on a number of unanswered questions in fluid mechanics, but has also identified a number of new issues of importance for their future deployment. The main concerns relevant to the practical use of wave energy converters are sustainability, survivability, and maintainability. Of course, it is also necessary to maximize the capture per unit area of the structure as well as to minimize the cost. In this review, we consider some of the questions related to the topics of sustainability, survivability, and maintenance access, with respect to sea conditions, for generic wave energy converters with an emphasis on the oscillating wave surge converter. New analytical models that have been developed are a topic of particular discussion. It is also shown how existing numerical models have been pushed to their limits to provide answers to open questions relating to the operation and characteristics of wave energy converters.

Analytical and computational modelling for wave energy systems: the example of oscillating wave surge converters.

Science.gov (United States)

Dias, Frédéric; Renzi, Emiliano; Gallagher, Sarah; Sarkar, Dripta; Wei, Yanji; Abadie, Thomas; Cummins, Cathal; Rafiee, Ashkan

2017-01-01

The development of new wave energy converters has shed light on a number of unanswered questions in fluid mechanics, but has also identified a number of new issues of importance for their future deployment. The main concerns relevant to the practical use of wave energy converters are sustainability, survivability, and maintainability. Of course, it is also necessary to maximize the capture per unit area of the structure as well as to minimize the cost. In this review, we consider some of the questions related to the topics of sustainability, survivability, and maintenance access, with respect to sea conditions, for generic wave energy converters with an emphasis on the oscillating wave surge converter. New analytical models that have been developed are a topic of particular discussion. It is also shown how existing numerical models have been pushed to their limits to provide answers to open questions relating to the operation and characteristics of wave energy converters.

Computing wave functions in multichannel collisions with non-local potentials using the R-matrix method

Science.gov (United States)

Bonitati, Joey; Slimmer, Ben; Li, Weichuan; Potel, Gregory; Nunes, Filomena

2017-09-01

The calculable form of the R-matrix method has been previously shown to be a useful tool in approximately solving the Schrodinger equation in nuclear scattering problems. We use this technique combined with the Gauss quadrature for the Lagrange-mesh method to efficiently solve for the wave functions of projectile nuclei in low energy collisions (1-100 MeV) involving an arbitrary number of channels. We include the local Woods-Saxon potential, the non-local potential of Perey and Buck, a Coulomb potential, and a coupling potential to computationally solve for the wave function of two nuclei at short distances. Object oriented programming is used to increase modularity, and parallel programming techniques are introduced to reduce computation time. We conclude that the R-matrix method is an effective method to predict the wave functions of nuclei in scattering problems involving both multiple channels and non-local potentials. Michigan State University iCER ACRES REU.

Wecpos - Wave Energy Coastal Protection Oscillating System: A Numerical Assessment

Science.gov (United States)

Dentale, Fabio; Pugliese Carratelli, Eugenio; Rzzo, Gianfranco; Arsie, Ivan; Davide Russo, Salvatore

2010-05-01

� software it has been possible to evaluate the hydrodynamic interactions that occur between a regular wave, with different height and period characteristics. The RANS equations, coupled with the RNG turbulence model, have been integrated on a three-dimensional channel (90.0 x 6.0 x 8.0 m), using a numerical domain made of two mesh blocks: a general one containing the entire domain (cells size 0.30 cm) and the localized one on the device (cells size 0.10 cm). With the results, by assessing the rotational angle, angular velocity, hydraulic torque of the individual panel it has been possible to estimate the potential energy production. A Matlab/Simulink model has been built to estimate the production of electric energy by means of an oleodynamic system consisting of a piston and a turbine coupled with an electric generator. About the coastal protection, by estimating some characteristic parameters of the wave motion (zero-moment wave height Hmo, transmission coefficient Kt and the average free surface elevation), the behaviour of the WECPOS device has been analyzed for its ability in wave energy dissipation.

Energy flow characteristics of vector X-Waves

KAUST Repository

Salem, Mohamed; Bagci, Hakan

2011-01-01

The vector form of X-Waves is obtained as a superposition of transverse electric and transverse magnetic polarized field components. It is shown that the signs of all components of the Poynting vector can be locally changed using carefully chosen complex amplitudes of the transverse electric and transverse magnetic polarization components. Negative energy flux density in the longitudinal direction can be observed in a bounded region around the centroid; in this region the local behavior of the wave field is similar to that of wave field with negative energy flow. This peculiar energy flux phenomenon is of essential importance for electromagnetic and optical traps and tweezers, where the location and momenta of microand nanoparticles are manipulated by changing the Poynting vector, and in detection of invisibility cloaks. © 2011 Optical Society of America.

Characterization of U.S. Wave Energy Converter (WEC) Test Sites: A Catalogue of Met-Ocean Data.

Energy Technology Data Exchange (ETDEWEB)

Dallman, Ann Renee; Neary, Vincent Sinclair

2014-10-01

This report presents met - ocean data and wave energy characteristics at three U.S. wave energy converter (WEC) test and potential deployment sites . Its purpose is to enable the compari son of wave resource characteristics among sites as well as the select io n of test sites that are most suitable for a developer's device and that best meet their testing needs and objectives . It also provides essential inputs for the design of WEC test devices and planning WEC tests, including the planning of deployment and op eration s and maintenance. For each site, this report catalogues wave statistics recommended in the (draft) International Electrotechnical Commission Technical Specification (IEC 62600 - 101 TS) on Wave Energy Characterization, as well as the frequency of oc currence of weather windows and extreme sea states, and statistics on wind and ocean currents. It also provides useful information on test site infrastructure and services .

A framework for assessing the uncertainty in wave energy delivery to targeted subsurface formations

KAUST Repository

Karve, Pranav M.

2016-02-01

© 2015 Elsevier B.V. Stress wave stimulation of geological formations has potential applications in petroleum engineering, hydro-geology, and environmental engineering. The stimulation can be applied using wave sources whose spatio-temporal characteristics are designed to focus the emitted wave energy into the target region. Typically, the design process involves numerical simulations of the underlying wave physics, and assumes a perfect knowledge of the material properties and the overall geometry of the geostructure. In practice, however, precise knowledge of the properties of the geological formations is elusive, and quantification of the reliability of a deterministic approach is crucial for evaluating the technical and economical feasibility of the design. In this article, we discuss a methodology that could be used to quantify the uncertainty in the wave energy delivery. We formulate the wave propagation problem for a two-dimensional, layered, isotropic, elastic solid truncated using hybrid perfectly-matched-layers (PMLs), and containing a target elastic or poroelastic inclusion. We define a wave motion metric to quantify the amount of the delivered wave energy. We, then, treat the material properties of the layers as random variables, and perform a first-order uncertainty analysis of the formation to compute the probabilities of failure to achieve threshold values of the motion metric. We illustrate the uncertainty quantification procedure using synthetic data.

Quasi-static analysis of wave loadings on spine-based wave energy devices

Energy Technology Data Exchange (ETDEWEB)

Lockett, F.P.; Peatfield, A.M.; West, M.J.

1980-02-01

A report is given on the Wave Energy Research Programme at Lanchester Polytechnic. Results are presented for both theoretical and experimental scale models for wave loadings on circular and rectangular spines of various lengths. The results are in good agreement over the operational wave range for the 1/50 scale model and for the more limited data on the 1/10 scale model.

Investigation of Wave Height Reduction behind the Wave Dragon Wave Energy Converters and Application in Santander, Spain

DEFF Research Database (Denmark)

Nørgaard, Jørgen Quvang Harck; Andersen, Thomas Lykke

This paper deals with a case study on the wave height reduction behind floating Wave Dragon wave energy converters in Santander Bay, Spain. The study is performed using the MIKE21 Boussinesq model from DHI. The Wave Dragon transmission characteristics in the numerical wave propagation model...... are based on previously performed physical model tests in scale 1:51. Typical winter storm conditions are considered in the case study together with different stiffness in the mooring system of the floating device. From the study it is found that if multiple Wave Dragons are positioned in a farm the wave...

What can wave energy learn from offshore oil and gas?

Science.gov (United States)

Jefferys, E R

2012-01-28

This title may appear rather presumptuous in the light of the progress made by the leading wave energy devices. However, there may still be some useful lessons to be learnt from current 'offshore' practice, and there are certainly some awful warnings from the past. Wave energy devices and the marine structures used in oil and gas exploration as well as production share a common environment and both are subject to wave, wind and current loads, which may be evaluated with well-validated, albeit imperfect, tools. Both types of structure can be designed, analysed and fabricated using similar tools and technologies. They fulfil very different missions and are subject to different economic and performance requirements; hence 'offshore' design tools must be used appropriately in wave energy project and system design, and 'offshore' cost data should be adapted for 'wave' applications. This article reviews the similarities and differences between the fields and highlights the differing economic environments; offshore structures are typically a small to moderate component of field development cost, while wave power devices will dominate overall system cost. The typical 'offshore' design process is summarized and issues such as reliability-based design and design of not normally manned structures are addressed. Lessons learned from poor design in the past are discussed to highlight areas where care is needed, and wave energy-specific design areas are reviewed. Opportunities for innovation and optimization in wave energy project and device design are discussed; wave energy projects must ultimately compete on a level playing field with other routes to low CO₂ energy and/or energy efficiency. This article is a personal viewpoint and not an expression of a ConocoPhillips position.

Wave energy transfer in elastic half-spaces with soft interlayers.

Science.gov (United States)

Glushkov, Evgeny; Glushkova, Natalia; Fomenko, Sergey

2015-04-01

The paper deals with guided waves generated by a surface load in a coated elastic half-space. The analysis is based on the explicit integral and asymptotic expressions derived in terms of Green's matrix and given loads for both laminate and functionally graded substrates. To perform the energy analysis, explicit expressions for the time-averaged amount of energy transferred in the time-harmonic wave field by every excited guided or body wave through horizontal planes and lateral cylindrical surfaces have been also derived. The study is focused on the peculiarities of wave energy transmission in substrates with soft interlayers that serve as internal channels for the excited guided waves. The notable features of the source energy partitioning in such media are the domination of a single emerging mode in each consecutive frequency subrange and the appearance of reverse energy fluxes at certain frequencies. These effects as well as modal and spatial distribution of the wave energy coming from the source into the substructure are numerically analyzed and discussed.

An Appraisal of the DEXA Wave Energy Converter

DEFF Research Database (Denmark)

Pecher, Arthur; Kofoed, Jens Peter

This report has been requested by VækstFonden and aims at giving an overview of the experimental tests and a general appraisal of the DEXA wave energy converter (WEC). The reported results and findings were obtained during previously performed experimental tests by the Wave Energy Research Group...

Direct Drive Wave Energy Buoy

Energy Technology Data Exchange (ETDEWEB)

Rhinefrank, Kenneth E. [Columbia Power Technologies, Inc.; Lenee-Bluhm, Pukha [Columbia Power Technologies, Inc.; Prudell, Joseph H. [Columbia Power Technologies, Inc.; Schacher, Alphonse A. [Columbia Power Technologies, Inc.; Hammagren, Erik J. [Columbia Power Technologies, Inc.; Zhang, Zhe [Columbia Power Technologies, Inc.

2013-07-29

The most prudent path to a full-scale design, build and deployment of a wave energy conversion (WEC) system involves establishment of validated numerical models using physical experiments in a methodical scaling program. This Project provides essential additional rounds of wave tank testing at 1:33 scale and ocean/bay testing at a 1:7 scale, necessary to validate numerical modeling that is essential to a utility-scale WEC design and associated certification.

Communicating Wave Energy: An Active Learning Experience for Students

Science.gov (United States)

Huynh, Trongnghia; Hou, Gene; Wang, Jin

2016-01-01

We have conducted an education project to communicate the wave energy concept to high school students. A virtual reality system that combines both hardware and software is developed in this project to simulate the buoy-wave interaction. This first-of-its-kind wave energy unit is portable and physics-based, allowing students to conduct a number of…

Numerical Forecasting Experiment of the Wave Energy Resource in the China Sea

Directory of Open Access Journals (Sweden)

Chong Wei Zheng

2016-01-01

Full Text Available The short-term forecasting of wave energy is important to provide guidance for the electric power operation and power transmission system and to enhance the efficiency of energy capture and conversion. This study produced a numerical forecasting experiment of the China Sea wave energy using WAVEWATCH-III (WW3, the latest version 4.18 wave model driven by T213 (WW3-T213 and T639 (WW3-T639 wind data separately. Then the WW3-T213 and WW3-T639 were verified and compared to build a short-term wave energy forecasting structure suited for the China Sea. Considering the value of wave power density (WPD, “wave energy rose,” daily and weekly total storage and effective storage of wave energy, this study also designed a series of short-term wave energy forecasting productions. Results show that both the WW3-T213 and WW3-T639 exhibit a good skill on the numerical forecasting of the China Sea WPD, while the result of WW3-T639 is much better. Judging from WPD and daily and weekly total storage and effective storage of wave energy, great wave energy caused by cold airs was found. As there are relatively frequent cold airs in winter, early spring, and later autumn in the China Sea and the surrounding waters, abundant wave energy ensues.

Further Development of SNL‐Swan, a Validated Wave Energy Converter

OpenAIRE

Porter, Aaron; Ruehl, Kelley; Chartrand, Chris

2014-01-01

Commercialization of wave energy will lead to the necessary deployment of Wave Energy Converters (WECs) in arrays, or wave farms. In order for projects in the United States to be approved, regulatory agencies must perform an Environmental Assessment proving little to no environmental impact. However, little is known about the environmental impacts of such wave farms. As a result, the environmental impacts of wave farms are largely determined by numerical wave models capable of modeling large ...

Surface-wave potential for triggering tectonic (nonvolcanic) tremor

Science.gov (United States)

Hill, D.P.

2010-01-01

Source processes commonly posed to explain instances of remote dynamic triggering of tectonic (nonvolcanic) tremor by surface waves include frictional failure and various modes of fluid activation. The relative potential for Love- and Rayleigh-wave dynamic stresses to trigger tectonic tremor through failure on critically stressed thrust and vertical strike-slip faults under the Coulomb-Griffith failure criteria as a function of incidence angle is anticorrelated over the 15- to 30-km-depth range that hosts tectonic tremor. Love-wave potential is high for strike-parallel incidence on low-angle reverse faults and null for strike-normal incidence; the opposite holds for Rayleigh waves. Love-wave potential is high for both strike-parallel and strike-normal incidence on vertical, strike-slip faults and minimal for ~45?? incidence angles. The opposite holds for Rayleigh waves. This pattern is consistent with documented instances of tremor triggered by Love waves incident on the Cascadia mega-thrust and the San Andreas fault (SAF) in central California resulting from shear failure on weak faults (apparent friction, ????? 0.2). However, documented instances of tremor triggered by surface waves with strike-parallel incidence along the Nankai megathrust beneath Shikoku, Japan, is associated primarily with Rayleigh waves. This is consistent with the tremor bursts resulting from mixed-mode failure (crack opening and shear failure) facilitated by near-lithostatic ambient pore pressure, low differential stress, with a moderate friction coefficient (?? ~ 0.6) on the Nankai subduction interface. Rayleigh-wave dilatational stress is relatively weak at tectonic tremor source depths and seems unlikely to contribute significantly to the triggering process, except perhaps for an indirect role on the SAF in sustaining tremor into the Rayleigh-wave coda that was initially triggered by Love waves.

On Mooring Solutions for Large Wave Energy Converters

DEFF Research Database (Denmark)

Thomsen, Jonas Bjerg; Kofoed, Jens Peter; Ferri, Francesco

2017-01-01

The present paper describes the work carried out in the project ’Mooring Solutions for Large Wave Energy Converters’, which is a Danish research project carried out in a period of three years from September 2014, with the aim of reducing cost of the moorings for four wave energy converters...

Experimental investigation on the hydrodynamic performance of a wave energy converter

Science.gov (United States)

Zheng, Xiong-bo; Ma, Yong; Zhang, Liang; Jiang, Jin; Liu, Heng-xu

2017-06-01

Wave energy is an important type of marine renewable energy. A wave energy converter (WEC) moored with two floating bodies was developed in the present study. To analyze the dynamic performance of the WEC, an experimental device was designed and tested in a tank. The experiment focused on the factors which impact the motion and energy conversion performance of the WEC. Dynamic performance was evaluated by the relative displacements and velocities of the oscillator and carrier which served as the floating bodies of WEC. Four factors were tested, i.e. wave height, wave period, power take-off (PTO) damping, and mass ratio ( R M) of the oscillator and carrier. Experimental results show that these factors greatly affect the energy conversion performance, especially when the wave period matches R M and PTO damping. According to the results, we conclude that: (a) the maximization of the relative displacements and velocities leads to the maximization of the energy conversion efficiency; (b) the larger the wave height, the higher the energy conversion efficiency will be; (c) the relationships of energy conversion efficiency with wave period, PTO damping, and R M are nonlinear, but the maximum efficiency is obtained when these three factors are optimally matched. Experimental results demonstrated that the energy conversion efficiency reached the peak at 28.62% when the wave height was 120 mm, wave period was 1.0 s, R M was 0.21, and the PTO damping was corresponding to the resistance of 100 Ω.

Assessment of the Wave Energy in the Black Sea Based on a 15-Year Hindcast with Data Assimilation

Directory of Open Access Journals (Sweden)

Liliana Rusu

2015-09-01

Full Text Available The principal target of the present work is to assess the wave energy potential in the Black Sea, identifying also some relevant energetic features and possible patterns. A wave prediction system based on the Simulating Waves Nearshore model (SWAN has been implemented and intensively tested in the entire sea basin. Moreover, considering an optimal interpolation technique, an assimilation scheme of the satellite data has been developed, leading to a visible improvement of the wave model predictions in terms of significant wave heights and, consequently, also in terms of wave power. Using this wave prediction system with data assimilation, simulations have been performed for a 15-year period (1999–2013. Considering the results of this 15-year wave hindcast, an analysis of the wave energy conditions in the basin of the Black Sea has been carried out. This provided a more comprehensive picture concerning the wave energy patterns in the coastal environment of the Black Sea focused on the average wave conditions that might be expected in this sea. Following the results presented, it can be concluded that the wave energy extraction in the Black Sea can become an issue of interest, especially from the perspective of the hybrid solutions.

Wave Energy, Lever Operated Pivoting Float LOPF Study

DEFF Research Database (Denmark)

Margheritini, Lucia

The fully instrumented Resen Waves Lever Operated Pivoting Float LOPF wave energy buoy model has gone through the first stage of testing in regular waves in scale 1:25 of the North Sea wave conditions, in the 3D deep wave basin at the Hydraulic and Coastal Engineering Laboratory of Aalborg...... University in Denmark. The model size was 60cm W x 90cm L x 21cm H. The 60 cm width pointed towards the wave front. The LOPF buoy is characterized by a simple mechanical design with few moving parts and direct electrical output and it is taut moored to the sea bed, so all forces are referenced to the seabed...... for maximum energy output in regular as well as irregular waves. During storms the buoy pivots and streamlines itself to minimize loads on the mooring line. A conservative estimate shows that a full scale system for North Sea conditions has a float size width of 15 m that will, with 60% generator efficiency...

Energy analysis of four dimensional extended hyperbolic Scarf I plus three dimensional separable trigonometric noncentral potentials using SUSY QM approach

International Nuclear Information System (INIS)

Suparmi, A.; Cari, C.; Deta, U. A.; Handhika, J.

2016-01-01

The non-relativistic energies and wave functions of extended hyperbolic Scarf I plus separable non-central shape invariant potential in four dimensions are investigated using Supersymmetric Quantum Mechanics (SUSY QM) Approach. The three dimensional separable non-central shape invariant angular potential consists of trigonometric Scarf II, Manning Rosen and Poschl-Teller potentials. The four dimensional Schrodinger equation with separable shape invariant non-central potential is reduced into four one dimensional Schrodinger equations through variable separation method. By using SUSY QM, the non-relativistic energies and radial wave functions are obtained from radial Schrodinger equation, the orbital quantum numbers and angular wave functions are obtained from angular Schrodinger equations. The extended potential means there is perturbation terms in potential and cause the decrease in energy spectra of Scarf I potential. (paper)

Wave propagation of spectral energy content in a granular chain

NARCIS (Netherlands)

Shrivastava, Rohit Kumar; Luding, Stefan

2017-01-01

A mechanical wave is propagation of vibration with transfer of energy and momentum. Understanding the spectral energy characteristics of a propagating wave through disordered granular media can assist in understanding the overall properties of wave propagation through inhomogeneous materials like

Recent Developments of Wave Energy Utilization in Denmark

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter; Kramer, Morten

2006-01-01

by a more thorough description of three ongoing projects. These are Wave Dragon, Wave Star and Seawave Slot-cone Generator. Common for these projects are that they are being, or will soon be, tested in real sea and have benefited from the Danish Wave Energy Program. The work by the department......This paper aims at giving an overview of the developments researchers at the Department of Civil Engineering, Aalborg University, Denmark (DCE), have been involved in within the field of wave energy utilization in Denmark over the past decade. At first a general introduction is given followed...... on these projects involves substantial laboratory testing, numerical simulations and real sea prototype testing....

Effects of Damping Plate and Taut Line System on Mooring Stability of Small Wave Energy Converter

Directory of Open Access Journals (Sweden)

Zhen Liu

2015-01-01

Full Text Available Ocean wave energy can be used for electricity supply to ocean data acquisition buoys. A heaving buoy wave energy converter is designed and the damping plate and taut line system are used to provide the mooring stability for better operating conditions. The potential flow assumption is employed for wave generation and fluid structure interactions, which are processed by the commercial software AQWA. Effects of damping plate diameter and taut line linking style with clump and seabed weights on reduction of displacements in 6 degrees of freedom are numerically studied under different operating wave conditions. Tensile forces on taut lines of optimized mooring system are tested to satisfy the national code for wire rope utilization.

Dominant wave frequency and amplitude estimation for adaptive control of wave energy converters

OpenAIRE

Nguyen , Hoai-Nam; Tona , Paolino; Sabiron , Guillaume

2017-01-01

International audience; Adaptive control is of great interest for wave energy converters (WEC) due to the inherent time-varying nature of sea conditions. Robust and accurate estimation algorithms are required to improve the knowledge of the current sea state on a wave-to-wave basis in order to ensure power harvesting as close as possible to optimal behavior. In this paper, we present a simple but innovative approach for estimating the wave force dominant frequency and wave force dominant ampl...

Designing a point-absorber wave energy converter for the Mediterranean Sea

International Nuclear Information System (INIS)

Archetti, Renata; Moreno Miquel, Adria; Antonini, Alessandro; Passoni, Giuseppe; Bozzi, Silvia; Gruosso, Giambattista; Scarpa, Francesca; Bizzozero, Federica; Giassi, Marianna

2015-01-01

This work aims to assess the potential for wave energy production in the Italian seas by the deployment of arrays of heaving point absorbers, specifically optimized for mild climates. We model a single-body WEC, consisting of a cylindrical heaving buoy, attached to a linear electric generator placed on the seabed. The model includes both hydrodynamic and electromechanical forces. The results show that the best buoy-generator configuration at the selected sites (Alghero and Mazara del Vallo) is given by a 6 to 10 kW device and with a buoy with diameter between 4 and 5 m. This device can be brought to resonance, increasing the performances, by adding a submerged sphere. These results are encouraging and enlarge the perspective on wave energy production in the Italian seas. [it

Transformation of Elastic Wave Energy to the Energy of Motion of Bodies

Science.gov (United States)

Vesnitskiĭ, A. I.; Lisenkova, E. E.

2002-01-01

The motion of a body along an elastic guide under the effect of an incident wave is considered. An equation describing the longitudinal motion of a body along an arbitrary guide is derived from the laws governing the energy and momentum variations for the case when the incident wave generates a single reflected wave. The equations that describe the motion of a body along a string and along a beam corresponding to the Bernoulli-Euler model are considered as examples. The process of the body acceleration along a beam of the aforementioned type is investigated. For the subcritical velocities, the law governing the motion of the body and the ratio of the kinetic energy variation to the energy supplied to the body are determined.

Wave-particle energy exchange directly observed in a kinetic Alfvén-branch wave.

Science.gov (United States)

Gershman, Daniel J; F-Viñas, Adolfo; Dorelli, John C; Boardsen, Scott A; Avanov, Levon A; Bellan, Paul M; Schwartz, Steven J; Lavraud, Benoit; Coffey, Victoria N; Chandler, Michael O; Saito, Yoshifumi; Paterson, William R; Fuselier, Stephen A; Ergun, Robert E; Strangeway, Robert J; Russell, Christopher T; Giles, Barbara L; Pollock, Craig J; Torbert, Roy B; Burch, James L

2017-03-31

Alfvén waves are fundamental plasma wave modes that permeate the universe. At small kinetic scales, they provide a critical mechanism for the transfer of energy between electromagnetic fields and charged particles. These waves are important not only in planetary magnetospheres, heliospheres and astrophysical systems but also in laboratory plasma experiments and fusion reactors. Through measurement of charged particles and electromagnetic fields with NASA's Magnetospheric Multiscale (MMS) mission, we utilize Earth's magnetosphere as a plasma physics laboratory. Here we confirm the conservative energy exchange between the electromagnetic field fluctuations and the charged particles that comprise an undamped kinetic Alfvén wave. Electrons confined between adjacent wave peaks may have contributed to saturation of damping effects via nonlinear particle trapping. The investigation of these detailed wave dynamics has been unexplored territory in experimental plasma physics and is only recently enabled by high-resolution MMS observations.

A Detailed Assessment of the Wave Energy Resource at the Atlantic Marine Energy Test Site

Directory of Open Access Journals (Sweden)

Reduan Atan

2016-11-01

Full Text Available Wave characteristic assessments of wave energy test sites provide a greater understanding of prevailing wave conditions and are therefore extremely important to both wave energy test site operators and clients as they can inform wave energy converter design, optimisation, deployment, operation and maintenance. This research presents an assessment of the wave resource at the Atlantic Marine Energy Test Site (AMETS on the west coast of Ireland based on 12-years of modelled data from January 2004 to December 2015. The primary aim is to provide an assessment of annual and seasonal wave characteristics and resource variability at the two deployment berths which comprise the site. A nested model has been developed using Simulating WAves Nearshore (SWAN to replicate wave propagations from regional to local scale with a 0.05° resolution model covering the northeast Atlantic and a 0.0027° resolution model covering AMETS. The coarse and fine models have been extensively validated against available measured data within Irish waters. 12-year model outputs from the high resolution model were analysed to determine mean and maximum conditions and operational, high and extreme event conditions for significant wave height, energy period and power. Annual and seasonal analyses are presented. The 12-year annual mean P were 68 kW/m at Berth A (BA and 57 kW/m at Berth B (BB. The resource shows strong seasonal and annual variations and the winter mean power levels were found to be strongly correlated with the North Atlantic Oscillation (NAO.

The Wave Energy Device

DEFF Research Database (Denmark)

Frigaard, Peter; Kofoed, Jens Peter; Tedd, James William

2006-01-01

's first offshore wave energy converter. During this period an extensive measuring program has established the background for optimal design of the structure and regulation of the power take off system. Planning for full scale deployment of a 7 MW unit within the next 2 years is in progress. The prototype...

Energy Relations for Plane Waves Reflected from Moving Media

DEFF Research Database (Denmark)

Daly, P.; Gruenberg, Harry

1967-01-01

When a plane wave is obliquely incident from vacuum on a semi-infinite moving medium, the energy flow carried by the incident wave, is in general, not carried away by the reflected and transmitted waves. This is only the case when the medium velocity is parallel to its vacuum interface. Otherwise...... there is a net inflow or outflow of electromagnetic energy, which can be accounted for by the change of stored energy in the system, and the work done by the mechanical forces acting on the medium. A detailed energy balance is drawn up for two different media moving normal to their vacuum interfaces: (a...

Measurements of Overtopping Flow Time Series on the Wave Dragon, Wave Energy Converter

DEFF Research Database (Denmark)

Tedd, James; Kofoed, Jens Peter

2009-01-01

A study of overtopping flow series on the Wave Dragon prototype, a low crested device designed to maximise flow, in a real sea, is presented. This study aims to fill the gap in the literature on time series of flow overtopping low crested structures. By comparing to a simulated flow the character......A study of overtopping flow series on the Wave Dragon prototype, a low crested device designed to maximise flow, in a real sea, is presented. This study aims to fill the gap in the literature on time series of flow overtopping low crested structures. By comparing to a simulated flow...... the characteristics of the overtopping flow are discussed and the simulation algorithm is tested. Measured data is shown from a storm build up in October 2006, from theWave Dragon prototype situated in an inland sea in Northern Denmark. This wave energy converter extracts energy from the waves, by funnelling them...

Resonant wave energy harvester based on dielectric elastomer generator

Science.gov (United States)

Moretti, Giacomo; Pietro Rosati Papini, Gastone; Righi, Michele; Forehand, David; Ingram, David; Vertechy, Rocco; Fontana, Marco

2018-03-01

Dielectric elastomer generators (DEGs) are a class of capacitive solid-state devices that employ highly stretchable dielectrics and conductors to convert mechanical energy into high-voltage direct-current electricity. Their promising performance in terms of convertible energy and power density has been mostly proven in quasi-static experimental tests with prescribed deformation. However, the assessment of their ability in harvesting energy from a dynamic oscillating source of mechanical energy is crucial to demonstrate their effectiveness in practical applications. This paper reports a first demonstration of a DEG system that is able to convert the oscillating energy carried by water waves into electricity. A DEG prototype is built using a commercial polyacrylate film (VHB 4905 by 3M) and an experimental campaign is conducted in a wave-flume facility, i.e. an artificial basin that makes it possible to generate programmed small-scale waves at different frequencies and amplitudes. In resonant conditions, the designed system demonstrates the delivery of a maximum of 0.87 W of electrical power output and 0.64 J energy generated per cycle, with corresponding densities per unit mass of dielectric elastomer of 197 W kg-1 and 145 J kg-1. Additionally, a notable maximum fraction of 18% of the input wave energy is converted into electricity. The presented results provide a promising demonstration of the operation and effectiveness of ocean wave energy converters based on elastic capacitive generators.

Crest Level Optimization of the Multi Level Overtopping based Wave Energy Converter Seawave Slot-Cone Generator

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Osaland, E.

2005-01-01

The paper describes the optimization of the crest levels and geometrical layout of the SSG structure, focusing on maximizing the obtained potential energy in the overtopping water. During wave tank testing at AAU average overtopping rates into the individual reservoirs have been measured. The ini......The paper describes the optimization of the crest levels and geometrical layout of the SSG structure, focusing on maximizing the obtained potential energy in the overtopping water. During wave tank testing at AAU average overtopping rates into the individual reservoirs have been measured....... The initial tests led to an expression describing the derivative of the overtopping rate with respect to the vertical distance. Based on this, numerical optimizations of the crest levels, for a number of combinations of wave conditions, have been performed. The hereby found optimal crest levels have been...

Power Take-Off Simulation for Scale Model Testing of Wave Energy Converters

Directory of Open Access Journals (Sweden)

Scott Beatty

2017-07-01

Full Text Available Small scale testing in controlled environments is a key stage in the development of potential wave energy conversion technology. Furthermore, it is well known that the physical design and operational quality of the power-take off (PTO used on the small scale model can have vast effects on the tank testing results. Passive mechanical elements such as friction brakes and air dampers or oil filled dashpots are fraught with nonlinear behaviors such as static friction, temperature dependency, and backlash, the effects of which propagate into the wave energy converter (WEC power production data, causing very high uncertainty in the extrapolation of the tank test results to the meaningful full ocean scale. The lack of quality in PTO simulators is an identified barrier to the development of WECs worldwide. A solution to this problem is to use actively controlled actuators for PTO simulation on small scale model wave energy converters. This can be done using force (or torque-controlled feedback systems with suitable instrumentation, enabling the PTO to exert any desired time and/or state dependent reaction force. In this paper, two working experimental PTO simulators on two different wave energy converters are described. The first implementation is on a 1:25 scale self-reacting point absorber wave energy converter with optimum reactive control. The real-time control system, described in detail, is implemented in LabVIEW. The second implementation is on a 1:20 scale single body point absorber under model-predictive control, implemented with a real-time controller in MATLAB/Simulink. Details on the physical hardware, software, and feedback control methods, as well as results, are described for each PTO. Lastly, both sets of real-time control code are to be web-hosted, free for download, modified and used by other researchers and WEC developers.

Silicone-Based Triboelectric Nanogenerator for Water Wave Energy Harvesting.

Science.gov (United States)

Xiao, Tian Xiao; Jiang, Tao; Zhu, Jian Xiong; Liang, Xi; Xu, Liang; Shao, Jia Jia; Zhang, Chun Lei; Wang, Jie; Wang, Zhong Lin

2018-01-31

Triboelectric nanogenerator (TENG) has been proven to be efficient for harvesting water wave energy, which is one of the most promising renewable energy sources. In this work, a TENG with a silicone rubber/carbon black composite electrode was designed for converting the water wave energy into electricity. The silicone-based electrode with a soft texture provides a better contact with the dielectric film. Furthermore, a spring structure is introduced to transform low-frequency water wave motions into high-frequency vibrations. They together improve the output performance and efficiency of TENG. The output performances of TENGs are further enhanced by optimizing the triboelectric material pair and tribo-surface area. A spring-assisted TENG device with the segmented silicone rubber-based electrode structure was sealed into a waterproof box, which delivers a maximum power density of 2.40 W m -3 , as triggered by the water waves. The present work provides a new strategy for fabricating high-performance TENG devices by coupling flexible electrodes and spring structure for harvesting water wave energy.

Frequency and wavenumber selective excitation of spin waves through coherent energy transfer from elastic waves

OpenAIRE

Hashimoto, Yusuke; Bossini, Davide; Johansen, Tom H.; Saitoh, Eiji; Kirilyuk, Andrei; Rasing, Theo

2017-01-01

Using spin-wave tomography (SWaT), we have investigated the excitation and the propagation dynamics of optically-excited magnetoelastic waves, i.e. hybridized modes of spin waves and elastic waves, in a garnet film. By using time-resolved SWaT, we reveal the excitation dynamics of magnetoelastic waves through coherent-energy transfer between optically-excited pure-elastic waves and spin waves via magnetoelastic coupling. This process realizes frequency and wavenumber selective excitation of s...

Enhancement of particle-wave energy exchange by resonance sweeping

International Nuclear Information System (INIS)

Berk, H.L.; Breizman, B.N.

1995-10-01

It is shown that as the resonance condition of the particle-wave interaction is varied adiabatically, that the particles trapped in the wave will form phase space holes or clumps that can enhance the particle-wave energy exchange. This mechanism can cause much larger saturation levels of instabilities, and even allow the free energy associated with instability, to be tapped in a system that is linearly stable due to background dissipation

Energy independent optical potentials: construction and limitations

International Nuclear Information System (INIS)

Hussein, M.S.; Moniz, E.J.

1983-11-01

Properties of the energy-independent potential U sup(-) which is wave-function-equivalent to the usual optical potential U(E) are constructed and examined. A simple procedure is presented for constructing U sup(-) in the uniform medium, and physical examples are discussed. The general result for finite systems, a recursive expansion in powers of U(E), is used to investigate the multiple scattering expansion of U sup(-); the energy-independent potential is found to have serious short-comings for direct microscopic construction or phenomenological parametrization. The microscopic theory, as exemplified here by the multiple scattering approach, does not lead to a reliable approximation scheme. Phenomenological approaches to U sup(-) are unattractive because the physics does not guide the parametrization effectively: the structure of the nonlocality is not tied directly to the dynamics; Im U sup(-) changes sign; different elements of the physics, separate in U(E), are completely entangled in U sup(-). (Author) [pt

Interaction of two walkers: wave-mediated energy and force.

Science.gov (United States)

Borghesi, Christian; Moukhtar, Julien; Labousse, Matthieu; Eddi, Antonin; Fort, Emmanuel; Couder, Yves

2014-12-01

A bouncing droplet, self-propelled by its interaction with the waves it generates, forms a classical wave-particle association called a "walker." Previous works have demonstrated that the dynamics of a single walker is driven by its global surface wave field that retains information on its past trajectory. Here we investigate the energy stored in this wave field for two coupled walkers and how it conveys an interaction between them. For this purpose, we characterize experimentally the "promenade modes" where two walkers are bound and propagate together. Their possible binding distances take discrete values, and the velocity of the pair depends on their mutual binding. The mean parallel motion can be either rectilinear or oscillating. The experimental results are recovered analytically with a simple theoretical framework. A relation between the kinetic energy of the droplets and the total energy of the standing waves is established.

Analysis of the impacts of Wave Energy Converter arrays on the nearshore wave climate in the Pacific Northwest

Science.gov (United States)

O'Dea, A.; Haller, M. C.

2013-12-01

As concerns over the use of fossil fuels increase, more and more effort is being put into the search for renewable and reliable sources of energy. Developments in ocean technologies have made the extraction of wave energy a promising alternative. Commercial exploitation of wave energy would require the deployment of arrays of Wave Energy Converters (WECs) that include several to hundreds of individual devices. Interactions between WECs and ocean waves result in both near-field and far-field changes in the incident wave field, including a significant decrease in wave height and a redirection of waves in the lee of the array, referred to as the wave shadow. Nearshore wave height and direction are directly related to the wave radiation stresses that drive longshore currents, rip currents and nearshore sediment transport, which suggests that significant far-field changes in the wave field due to WEC arrays could have an impact on littoral processes. The goal of this study is to investigate the changes in nearshore wave conditions and radiation stress forcing as a result of an offshore array of point-absorber type WECs using a nested SWAN model, and to determine how array size, configuration, spacing and distance from shore influence these changes. The two sites of interest are the Northwest National Marine Renewable Energy Center (NNMREC) test sites off the coast of Newport Oregon, the North Energy Test Site (NETS) and the South Energy Test Site (SETS). NETS and SETS are permitted wave energy test sites located approximately 4 km and 10 km offshore, respectively. Twenty array configurations are simulated, including 5, 10, 25, 50 and 100 devices in two and three staggered rows in both closely spaced (three times the WEC diameter) and widely spaced (ten times the WEC diameter) arrays. Daily offshore wave spectra are obtained from a regional WAVEWATCH III hindcast for 2011, which are then propagated across the continental shelf using SWAN. Arrays are represented in SWAN

Survivability Mode and Extreme Loads on the Mooring Lines of the Wave Dragon Wave Energy Converter

DEFF Research Database (Denmark)

Parmeggiani, Stefano; Kofoed, Jens Peter

This report is a product of the cooperation agreement between Wave Dragon and Aalborg University regarding phase 2 of the development of the Wave Dragon Wave Energy Converter. The research is carried out by testing the 1:51.8 scale model of the Wave Dragon, aiming at the assessment of the surviva......This report is a product of the cooperation agreement between Wave Dragon and Aalborg University regarding phase 2 of the development of the Wave Dragon Wave Energy Converter. The research is carried out by testing the 1:51.8 scale model of the Wave Dragon, aiming at the assessment...... of the department of Civil Engineering at Aalborg University. The outcome of the research will be used as input for future research work aimed at the design of the mooring system and the certification of the structural design for the full scale Wave Dragon demonstrator....

Marine renewables: Exploring the opportunity for combining wind and wave energy

International Nuclear Information System (INIS)

Azzellino, Arianna; Riefolo, Luigia; Lanfredi, Caterina; Vicinanza, Diego

2015-01-01

Resource diversity is considered the key to manage the intrinsic variability of renewable energy sources and to lower their system integration costs. The expected development of Marine Renewable Energy Installations is likely to result in further transformation of coastal sea areas, already heavily impacted. In this perspective, the combination of different renewables and their potential impact on the environment must be evaluated in the context of the existing pressures. In this study the opportunity of co-locating offshore wind turbines and wave energy converters and their environmental sustainability is evaluated through a quantitative Marine Spatial Planning (MSP) approach. [it

Selection of Design Power of Wave Energy Converters Based on Wave Basin Experiments

DEFF Research Database (Denmark)

Martinelli, L.; Zanuttigh, B.; Kofoed, Jens Peter

2011-01-01

of the measured efficiency; description of the energy production by means of a function of the design capacity; application of a simple formula for cost benefit analysis. The analyses here proposed are based on the experimental results of 3D tests on two floating wave energy devices, named LEANCON and DEXA......Aim of this paper is to develop a method for selecting the optimal power generation capacity for which a wave energy converter (WEC) should be rated. This method is suitable for the earliest stages of development, when several studies are missing, including design of the Power Take Off (PTO) system...

Analysis of Energy Overshoot of High Frequency Waves with Wavelet Transform

Institute of Scientific and Technical Information of China (English)

WEN Fan

2000-01-01

A study is made on the overshoot phenomena in wind-generated waves. The surface displace ments of time-growing waves are measured at four fetches in a wind wave channel. The evolution of high frequency waves is displayed with wavelet transform. The results are compared with Sutherland＇s. It is found that high frequency wave components experience much stronger energy overshoot in the evolution.The energy of high frequency waves decreases greatly after overshoot

An array effect of wave energy farm buoys

Directory of Open Access Journals (Sweden)

Hyuck-Min Kweon

2012-12-01

Full Text Available An ocean buoy energy farm is considered for Green energy generation and delivery to small towns along the Korean coast. The present studypresents that the floating buoy-type energy farm appears to be sufficiently feasible fortrapping more energy compared to afixed cylinder duck array. It is also seen from the numerical resultsthat the resonated waves between spaced buoys are further trapped by floating buoy motion. Our numerical study is analyzed by a plane-wave approximation, in which evanescent mode effects are included in a modified mild-slope equation based on the scattering characteristics for a single buoy.

Double system wave energy converter for the breaker zone

International Nuclear Information System (INIS)

Malavasi, Stefano; Negri; Marco

2015-01-01

In this paper a particular type of wave energy converter, namely EDS (Energy Double System) is presented. It is a two-body point absorber composed by a heaving float and a surging paddle, mounted on the same structure and aligned along the wave propagation direction. The system is designed for working in the breaker zone, where waves close to breaking can generate a considerable surging force on the paddle. A scale EDS model has been built and tested in the wave flume of the Hydraulics Laboratory of the 'Politecnico' of Milan. The power absorbed by the system, varying its configuration, position and wave, has been measured, and interesting efficiencies have been found.

Design Specifications for the Hanstholm WEPTOS Wave Energy Converter

Directory of Open Access Journals (Sweden)

Tommy Larsen

2012-04-01

Full Text Available The WEPTOS wave energy converter (WEC is a novel device that combines an established and efficient wave energy absorbing mechanism with a smart structure, which can regulate the amount of incoming wave energy and reduce loads in extreme wave conditions. This adjustable A-shaped slack-moored and floating structure absorbs the energy of the waves through a multitude of rotors. The shape of the rotors is based on the renowned Salter’s Duck. On each leg, the rotors pivot around a common axle, through which the rotors transfer the absorbed power to a common power take off system. The study investigates the required capacity of the power take off (PTO system and the structural forces on a WEPTOS WEC prototype, intended for installation at Hanstholm (Denmark, based on large scale experimental tests using a highly realistic laboratory model of the complete device. The results hereof includes the rotational speed and transmitted torque (and hereby power to the PTO system using different PTO control strategies, the impact of fluctuations of the available mechanical power and the effect of limiting the PTO capacity on the annual energy production. Acquisition of structural forces includes mooring forces and structural bending moments in both production and extreme wave conditions, illustrating that the regulation of the angle in the A shape ensures that extreme forces on the structure can be kept in the same order of magnitude as in production conditions.

Building a wave energy policy focusing on innovation, manufacturing and deployment

International Nuclear Information System (INIS)

Dalton, G.; Gallachoir, B.P.O.

2010-01-01

The Irish Government has set a goal to make Ireland a world leader for research, development and deployment of ocean energy technologies. Ireland has a wave energy resource of 21 TWh and an ambition is to achieve at least 500 MW installed generating capacity from ocean energy by 2020. This paper investigates what is required to move from ambition to delivery. A successful wave energy strategy will require focused policies that will stimulate innovation to develop the technologies, manufacturing to produce the devices and deployment to build the required wave power plants. The paper draws on the successful policies in Ireland that have stimulated each of these dimensions, albeit for different sectors. From 2004 to 2008, successful policies in (ICT and biotech) innovation led to an increase in Ireland's Innovation Index score from 0.48 to 0.53. The policy focus on (food and pharmaceuticals) manufacturing in Ireland resulted in high levels of economic growth over the period 1998-2002, reaching >10% GDP growth levels per annum, and full employment. Successful wind energy policies deployment has accelerated rapidly since 2003 and reached 1.2 GW installed capacity in 2009 representing 15% of Ireland's total installed capacity. The paper draws on appropriate elements of these policies to build a successful wave energy policy for Ireland. It also draws on the successful policies adopted in Denmark for innovation, manufacturing and deployment of wind energy. The Danish wind turbine manufacturers hold a world market share of approximately 40%. The paper proposes establishing a wave energy strategy group to develop an action plan to deliver the 500 MW. It also proposes a novel extension of corporate tax specifically for wave energy companies, an initial 30% capital grant scheme for wave energy developers, a grid code for wave energy devices and fast tracking of planning decisions through an amended approach to strategic infrastructure. (author)

On gravitational wave energy in Einstein gravitational theory

International Nuclear Information System (INIS)

Folomeshkin, V.N.; Vlasov, A.A.

1978-01-01

By the example of precise wave solutions for the Einstein equations it is shown that a standard commonly adopted formulation of energy-momentum problem with pseudotensors provides us either with a zero or sign-variable values for the energy of gravitational waves. It is shown that if in the Einstein gravitational theory a strict transition to the limits of weak fields is realised then the theory gives us an unambiguous zero result for weak gravitational waves. The well-known non-zero result arises due to incorrect transition to weak field approximation in the Einstein gravitation theory

Energy-flux characterization of conical and space-time coupled wave packets

International Nuclear Information System (INIS)

Lotti, A.; Couairon, A.; Faccio, D.; Trapani, P. Di

2010-01-01

We introduce the concept of energy density flux as a characterization tool for the propagation of ultrashort laser pulses with spatiotemporal coupling. In contrast with calculations for the Poynting vector, those for energy density flux are derived in the local frame moving at the velocity of the envelope of the wave packet under examination and do not need knowledge of the magnetic field. We show that the energy flux defined from a paraxial propagation equation follows specific geometrical connections with the phase front of the optical wave packet, which demonstrates that the knowledge of the phase fronts amounts to the measurement of the energy flux. We perform a detailed numerical study of the energy density flux in the particular case of conical waves, with special attention paid to stationary-envelope conical waves (X or O waves). A full characterization of linear conical waves is given in terms of their energy flux. We extend the definition of this concept to the case of nonlinear propagation in Kerr media with nonlinear losses.

Building a Pre-Competitive Knowledge Base to Support Australia's Wave Energy Industry

Science.gov (United States)

Hoeke, R. K.; Hemer, M. A.; Symonds, G.; Rosebrock, U.; Kenyon, R.; Zieger, S.; Durrant, T.; Contardo, S.; O'Grady, J.; Mcinnes, K. L.

2016-02-01

A pre-competitive, query-able and openly available spatio-temporal atlas of Australia's wind-wave energy resource and marine management uses is being delivered. To provide the best representation of wave energy resource information, accounting for both spatial and temporal characteristics of the resource, a 34+yr numerical hindcast of wave conditions in the Australian region has been developed. Considerable in situ and remotely sensed data have been collected to support calibration and validation of the hindcast, resulting in a high-quality characterisation of the available wave resource in the Australian domain. Planning for wave energy projects is also subject to other spatial constraints. Spatial information on alternative uses of the marine domain including, for example, fisheries and aquaculture, oil and gas, shipping, navigation and ports, marine parks and reserves, sub-sea cables and infrastructure, shipwrecks and sites of cultural significance, have been compiled to complement the spatial characterisation of resource and support spatial planning of future wave energy projects. Both resource and spatial constraint information are being disseminated via a state-of-the-art portal, designed to meet the needs of all industry stakeholders. Another aspect currently impeding the industry in Australia is the limited evidence-base of impacts of wave energy extraction on adjacent marine and coastal environments. To build this evidence base, a network of in situ wave measurement devices have been deployed surrounding the 3 wave energy converters of Carnegie Wave Energy Limited's Perth Wave Energy Project. This data is being used to calibrate and validate numerical simulations of the project site. Early stage results will be presented.

Internal wave energy radiated from a turbulent mixed layer

Energy Technology Data Exchange (ETDEWEB)

Munroe, James R., E-mail: jmunroe@mun.ca [Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John' s, Newfoundland A1B 3X7 (Canada); Sutherland, Bruce R., E-mail: bsuther@ualberta.ca [Departments of Physics and Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada)

2014-09-15

We examine mixed-layer deepening and the generation of internal waves in stratified fluid resulting from turbulence that develops in response to an applied surface stress. In laboratory experiments the stress is applied over the breadth of a finite-length tank by a moving roughened conveyor belt. The turbulence in the shear layer is characterized using particle image velocimetry to measure the kinetic energy density. The internal waves are measured using synthetic schlieren to determine their amplitudes, frequencies, and energy density. We also perform fully nonlinear numerical simulations restricted to two dimensions but in a horizontally periodic domain. These clearly demonstrate that internal waves are generated by transient eddies at the integral length scale of turbulence and which translate with the background shear along the base of the mixed layer. In both experiments and simulations we find that the energy density of the generated waves is 1%–3% of the turbulent kinetic energy density of the turbulent layer.

Relativistic Energy Analysis of Five-Dimensional q-Deformed Radial Rosen-Morse Potential Combined with q-Deformed Trigonometric Scarf Noncentral Potential Using Asymptotic Iteration Method

International Nuclear Information System (INIS)

Pramono, Subur; Suparmi, A.; Cari, Cari

2016-01-01

We study the exact solution of Dirac equation in the hyperspherical coordinate under influence of separable q-deformed quantum potentials. The q-deformed hyperbolic Rosen-Morse potential is perturbed by q-deformed noncentral trigonometric Scarf potentials, where all of them can be solved by using Asymptotic Iteration Method (AIM). This work is limited to spin symmetry case. The relativistic energy equation and orbital quantum number equation l_D_-_1 have been obtained using Asymptotic Iteration Method. The upper radial wave function equations and angular wave function equations are also obtained by using this method. The relativistic energy levels are numerically calculated using Matlab, and the increase of radial quantum number n causes the increase of bound state relativistic energy level in both dimensions D=5 and D=3. The bound state relativistic energy level decreases with increasing of both deformation parameter q and orbital quantum number n_l.

Power converter for raindrop energy harvesting application: Half-wave rectifier

Science.gov (United States)

Izrin, Izhab Muhammad; Dahari, Zuraini

2017-10-01

Harvesting raindrop energy by capturing vibration from impact of raindrop have been explored extensively. Basically, raindrop energy is generated by converting the kinetic energy of raindrop into electrical energy by using polyvinylidene fluoride (PVDF) piezoelectric. In this paper, a power converter using half-wave rectifier for raindrop harvesting energy application is designed and proposed to convert damping alternating current (AC) generated by PVDF into direct current (DC). This research presents parameter analysis of raindrop simulation used in the experiment and resistive load effect on half-wave rectifier converter. The experiment is conducted by using artificial raindrop from the height of 1.3 m to simulate the effect of different resistive load on the output of half-wave rectifier converter. The results of the 0.68 MΩ resistive load showed the best performance of the half-wave rectifier converter used in raindrop harvesting energy system, which generated 3.18 Vaverage. The peak instantaneous output generated from this experiment is 15.36 µW.

Probabilistic Forecasting of the Wave Energy Flux

DEFF Research Database (Denmark)

Pinson, Pierre; Reikard, G.; Bidlot, J.-R.

2012-01-01

Wave energy will certainly have a significant role to play in the deployment of renewable energy generation capacities. As with wind and solar, probabilistic forecasts of wave power over horizons of a few hours to a few days are required for power system operation as well as trading in electricit......% and 70% in terms of Continuous Rank Probability Score (CRPS), depending upon the test case and the lead time. It is finally shown that the log-Normal assumption can be seen as acceptable, even though it may be refined in the future....

Research on a new wave energy absorption device

Science.gov (United States)

Lu, Zhongyue; Shang, Jianzhong; Luo, Zirong; Sun, Chongfei; Zhu, Yiming

2018-01-01

To reduce impact of global warming and the energy crisis problems caused by pollution of energy combustion, the research on renewable and clean energies becomes more and more important. This paper designed a new wave absorption device, and also gave an introduction on its mechanical structure. The flow tube model is analyzed, and presented the formulation of the proposed method. To verify the principle of wave absorbing device, an experiment was carried out in a laboratory environment, and the results of the experiment can be applied for optimizing the structure design of output power.

Study of a Novel Oscillating Surge Wave Energy Converter: Preprint

Energy Technology Data Exchange (ETDEWEB)

Tom, Nathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Choiniere, Michael [University of Maine; Thiagarajan, Krish P. [University of Maine

2017-08-01

This study investigates the performance of an oscillating surge wave energy converter (OSWEC) that utilizes adjustable geometry as a means of controlling the hydrodynamic coefficients, a concept originally proposed by [1]. The body of the device consists of a bottom-hinged solid rectangular frame with five horizontal flaps spanning the interior of the frame. The flaps can rotate independently about their center of rotation within the frame like a large window shutter. Changing the orientation of the flaps alters the hydrodynamic coefficients and natural frequency of the device as well as the ability to shed or absorb structural loads accordingly. This ability may allow the device to operate in a wider range of sea states than other current wave energy converter designs. This paper presents and compares the results of numerical simulations and experimental testing of the OSWEC's response to regular waves with all five of the horizontal fin configurations sharing the same orientation of 0 degrees (fully closed interior) and 90 degrees (fully open). The numerical simulations were performed using WAMIT, which calculates hydrodynamic coefficients using a boundary element method code to solve the linear potential flow problem, and WEC-Sim, a MATLAB-based tool that simulates multibody devices in the time domain by solving the governing equations of motion. A 1:14 scale model of the device was built for experimental evaluation in an 8-m-long, 1-m wide wave tank, which supports a water depth of 0.7 m. The OSWEC motion in different wave conditions was measured with displacement sensors while nonlinear wave-structure interaction effects like slamming and overtopping were captured using a high-speed camera and used to understand differences between the simulation and experiments.

Assessment of Wave Energy in the South China Sea Based on GIS Technology

Directory of Open Access Journals (Sweden)

Gang Lin

2017-01-01

Full Text Available China is now the world’s largest user of coal and also has the highest greenhouse gas emissions associated with the mining and use of coal. Under today’s enormous pressures of the growing shortage of conventional energy sources and the need for emission reductions, the search for clean energy is the most effective strategy to address the energy crisis and global warming. This study utilized satellite remote sensing technology, geographic information system (GIS technology, and simulated wave data for the South China Sea. The characteristic features of the wave energy were obtained by analysis through the wave resource assessment formula and the results were stored in a GIS database. Software for the evaluation of wave energy in the South China Sea was written. The results should provide accurate, efficient references for wave energy researchers and decision-makers. Based on a 24-year WW3 model simulation wave data and GIS technology, this study presented the characteristic of the wave energy in the SCS; results demonstrated that the SCS has the feasibility and viability for wave energy farming.

Solitary wave dynamics in time-dependent potentials

International Nuclear Information System (INIS)

Abou Salem, Walid K.

2008-01-01

The long time dynamics of solitary wave solutions of the nonlinear Schroedinger equation in time-dependent external potentials is rigorously studied. To set the stage, the well-posedness of the Cauchy problem for a generalized nonautonomous nonlinear Schroedinger equation with time-dependent nonlinearities and potential is established. Afterward, the dynamics of NLS solitary waves in time-dependent potentials is studied. It is shown that in the space-adiabatic regime where the external potential varies slowly in space compared to the size of the soliton, the dynamics of the center of the soliton is described by Hamilton's equations, plus terms due to radiation damping. Finally, two physical applications are discussed: the first is adiabatic transportation of solitons and the second is the Mathieu instability of trapped solitons due to time-periodic perturbations

Transmission of wave energy in curved ducts

Science.gov (United States)

Rostafinski, W.

1973-01-01

A formation of wave energy flow was developed for motion in curved ducts. A parametric study over a range of frequencies determined the ability of circular bends to transmit energy for the case of perfectly rigid walls.

Investigation and Optimisation of a Discrete Fluid Power PTO-system for Wave Energy Converters

DEFF Research Database (Denmark)

Hansen, Anders Hedegaard

Patents on ocean wave energy dates back to 1799, however no wave energy converter (WEC) concept have a commercialised device. The cost of energy produced with wave energy converters is very high compared to traditional energy sources. Even when compared to energy from wind turbines wave energy...... investigation show how the wave climate naturally influence the optimal system configuration yielding maximal energy output, and how one may choose the system configuration based on the installation site. The switching manifold is the control element of the secondary controlled force system. The force...... needs cost reductions. Hence, next to political will, the main obstacle for a commercial break through of wave energy technology is the high cost of energy. Initiatives to lower costs are made in areas of minimising structural costs and increasing the energy production per device. Wave Star A/S has...

Electricity from wave and tide an introduction to marine energy

CERN Document Server

Lynn, Paul A

2014-01-01

This is a concise yet technically authoritative overview of modern marine energy devices with the goal of sustainable electricity generation. With 165 full-colour illustrations and photographs of devices at an advanced stage, the book provides inspiring case studies of today's most promising marine energy devices and developments, including full-scale grid-connected prototypes tested in sea conditions. It also covers the European Marine Energy Centre (EMEC) in Orkney, Scotland, where many of the devices are assessed. Topics discussed: global resources - drawing energy from the World's waves and tides history of wave and tidal stream systems theoretical background to modern developments conversion of marine energy into grid electricity modern wave energy converters and tidal stream energy converters. This book is aimed at a wide readership including professionals, policy makers and employees in the energy sector needing an introduction to marine energy. Its descriptive style and technical level will also appea...

Stratospheric gravity wave activities inferred through the GPS radio occultation technique

International Nuclear Information System (INIS)

Wrasse, Cristiano Max; Takahashi, Hisao; Fechine, Joaquim; Denardini, Clezio Marcos; Wickert, Jens

2007-01-01

Stratospheric gravity wave activities were deduced from GPS radio occultation temperature profiles obtained by CHAMP satellite between 2001 and 2005. Potential energy profiles are used to analyze the gravity wave activity over South America. The results showed an inter-annual variation of the potential energy integrated between 24 and 34 km of altitude. The gravity wave activity is more concentrated around the equatorial region. In order to evaluate the seasonal variation of the gravity wave activity, a mean potential energy was determined over (10 deg N-10 deg S) and (100 deg W-20 deg W). The results showed a lower gravity wave activity during winter time, while during spring time the mean potential energy showed an increase in the wave activity. The results of the mean potential energy also showed that the gravity wave activity in the lower stratosphere exhibits a higher wave activity during 2002 and 2004 and a lower wave activity during 2003 and 2005. (author)

The potential for using disused coastal mineshafts to exploit wave energy : Vol. 1: Main report; Vol. 2: Appendices

Energy Technology Data Exchange (ETDEWEB)

Scholes, H.; Millar, D.L.; Eyre, J.M.; Dibley, R.; Davey, G.; Haywood, M.

2004-07-01

This report summarises the findings of a project investigating the potential use of abandoned mine shafts in Cornwall as oscillating water column wave power generation devices, and assesses the Waveshaft concept in phase 1 prior to further examination of selected sites in phase 2. Details are given of the criteria for the mine shafts, identification of candidate shafts, remediation/enhancement requirements, and wave climate along with power conversion issues, overall estimated waveshaft resource in Cornwall, environmental impacts and legal protection, and an economic appraisal. Inspection and safety protocols, mine location maps, and wave power data are presented in appendices.

International Energy Agency Ocean Energy Systems Task 10 Wave Energy Converter Modeling Verification and Validation

DEFF Research Database (Denmark)

Wendt, Fabian F.; Yu, Yi-Hsiang; Nielsen, Kim

2017-01-01

This is the first joint reference paper for the Ocean Energy Systems (OES) Task 10 Wave Energy Converter modeling verification and validation group. The group is established under the OES Energy Technology Network program under the International Energy Agency. OES was founded in 2001 and Task 10 ...

Wave propagation of spectral energy content in a granular chain

Directory of Open Access Journals (Sweden)

Shrivastava Rohit Kumar

2017-01-01

Full Text Available A mechanical wave is propagation of vibration with transfer of energy and momentum. Understanding the spectral energy characteristics of a propagating wave through disordered granular media can assist in understanding the overall properties of wave propagation through inhomogeneous materials like soil. The study of these properties is aimed at modeling wave propagation for oil, mineral or gas exploration (seismic prospecting or non-destructive testing of the internal structure of solids. The focus is on the total energy content of a pulse propagating through an idealized one-dimensional discrete particle system like a mass disordered granular chain, which allows understanding the energy attenuation due to disorder since it isolates the longitudinal P-wave from shear or rotational modes. It is observed from the signal that stronger disorder leads to faster attenuation of the signal. An ordered granular chain exhibits ballistic propagation of energy whereas, a disordered granular chain exhibits more diffusive like propagation, which eventually becomes localized at long time periods. For obtaining mean-field macroscopic/continuum properties, ensemble averaging has been used, however, such an ensemble averaged spectral energy response does not resolve multiple scattering, leading to loss of information, indicating the need for a different framework for micro-macro averaging.

Energy cascading in the beat-wave accelerator

International Nuclear Information System (INIS)

McKinstrie, C.J.; Batha, S.H.

1987-01-01

A review is given of energy cascading in the beat-wave accelerator. The properties of the electromagnetic cascade and the corresponding plasma-wave evolution are well understood within the framework of an approximate analytic model. Based on this model, idealized laser-plasma coupling efficiencies of the order of 10% do not seem unreasonable. 28 refs

Oscillatory Energy Exchange Between Waves Coupled by a Dynamic Artificial Crystal

OpenAIRE

Karenowska, Alexy D.; Tiberkevich, Vasil S.; Chumak, Andrii V.; Serga, Alexander A.; Gregg, John F.; Slavin, Andrei N.; Hillebrands, Burkard

2011-01-01

We describe a general mechanism of controllable energy exchange between waves propagating in a dynamic artificial crystal. We show that if a spatial periodicity is temporarily imposed on the transmission properties of a wave-carrying medium whilst a wave is inside, this wave is coupled to a secondary counter-propagating wave and energy oscillates between the two. The oscillation frequency is determined by the width of the spectral band gap created by the periodicity and the frequency differen...

A nonlocal potential form for s-wave α-α scattering

International Nuclear Information System (INIS)

Amos, K.; Bennett, M.T.

1997-01-01

Low energy s-wave α-α phase shifts that agree well with the measured set, have been extracted using a nonlocal interaction formed by folding (local real) nucleon -α particle interactions with density matrix elements of the (projectile) α particle. The resultant nonlocal s-wave α-α interaction is energy dependent and has a nonlocality range of about 2 fm

Stochastic control applied to the ISWEC Wave Energy System

International Nuclear Information System (INIS)

Bracco, Giovanni; Casassa, Maria; Giorcelli, Ermanno; Mattiazzo, Giuliana; Passione, Biagio; Raffero, Mattia; Vissio, Giacomo; Martini, Michele

2015-01-01

ISWEC (Inertial Sea Wave Energy Converter) is a floating marine device able to harvest sea waves energy by the interaction between the pitching motion of a floater and a spinning flywheel which can drive an electric PTO. In the ISWEC the hull dynamics is governed and controlled by the gyroscopic torque. The optimal control logic results in tuning the floater dynamics to the incoming waves in order to maximize the power transfer from the waves to the floater. In this paper the control problems of the ISWEC are stated and a control scheme based on the sub-optimal stochastic control logic is presented. The control scheme here presented has been tested using real wave records acquired at the deployment location in Pantelleria Island, which is one of the most energetic sites of the Mediterranean Sea.

Aiding Design of Wave Energy Converters via Computational Simulations