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Showing papers on "Wave power published in 2017"


Journal ArticleDOI
09 Feb 2017-Nature
TL;DR: Zhong Lin Wang proposes a radically different way to harvest renewable energy from the ocean using nanogenerator networks.
Abstract: Zhong Lin Wang proposes a radically different way to harvest renewable energy from the ocean using nanogenerator networks.

457 citations


Journal ArticleDOI
TL;DR: In this article, the authors provide a concise review of the current state of ocean wave energy conversion technologies and industry status in the United States including research and development as well as commercial activities and governmental support.
Abstract: Ocean waves are a more predictable resource with a higher energy density compared to solar and wind. In addition, and specifically for the United States, resource locations with high wave power are close to major load centers being located along coastlines. These features have sparked a surge of attention in the United States on trying to economically harness ocean wave power. The aim of this article is to provide a concise review of the current state of ocean wave energy conversion technologies and industry status in the United States including research and development as well as commercial activities and governmental support, concluding with a discussion of future industry perspectives. Existing facilities, softwares as well as laboratory and open-water test facilities and resources, active research groups and commercial activities have been identified. Over one third of commercially active wave energy developers worldwide are located within the United States, but only a few have reached a high Technology Readiness Level. These findings, together with a relevant practical resource located within the U.S. and the advantageous nature of the resource compared to other renewable resources, indicate that the United States is well positioned to advance the wave energy industry in the near future.

143 citations


Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the global wave energy resources according to the most recent datasets available, to identify the locations with the worldwide highest wave energy potential and to assess in those locations the performance of some state-of-the-art wave energy converters.
Abstract: The main objectives of the present work are to review the global wave energy resources according to the most recent datasets available, to identify the locations with the worldwide highest wave energy potential and to assess in those locations the performance of some state-of-the-art wave energy converters. For this purpose, 15 years of wave data provided by the European Centre for Medium-Range Weather Forecasts, covering the time interval 2000–2014, were considered, processed and analysed. After identifying the geographical regions with the highest wave power, 15 reference points, which were considered more relevant from the point of view of their wave energy potential, have been defined in each hemisphere (northern and southern, respectively). As a following step, corresponding to all of these reference points, the most relevant wave patterns have been identified, and this information was subsequently used to assess the expected power output of the wave energy converters considered. Some other relevant parameters, such as the capacity factor or the capture width, were evaluated as well. Following the results provided by this work, we can expect that most of the existent devices for harnessing wave energy would perform well near most of the coastal environments identified. Moreover, it also must be highlighted that in the future, wave energy farms can play a very active role from the point of view of coastal protection.

103 citations


Journal ArticleDOI
TL;DR: In this article, a series of wave-flume experiments were conducted in regular waves to examine the wave power extraction of a floating box-type breakwater with dual pneumatic chambers.

75 citations


Journal ArticleDOI
TL;DR: In this paper, a new method is proposed for predicting wave energy resources on a medium-to-long-term basis that incorporates the swell index and propagation characteristics of swell energy.
Abstract: Against a backdrop of increasing energy demand, the development of wave energy technology is a logical means of both meeting this demand and mitigating the environmental degradation associated with conventional power generation. Previous research has made considerable progress in the climatic characterization and short-term forecasting of wave energy. However, medium- to long-term predictions of wave energy resources, which are central to the development of future operating and trading strategies, remain scarce. This study provides an overview of long-term climatic trends and medium- to long-term predictions of wave energy, before discussing the focus of future predictions. Finally, a new method is proposed for predicting wave energy resources on a medium- to long-term basis that incorporates the swell index and propagation characteristics of swell energy. This model was developed with the aim of improving the precision of wave energy predictions, thereby providing a reference for the effective utilization of wave resources. The results of this study demonstrate that long-term climatic trend analysis should include not only variations in wave power density (WPD), but also long-term variability in wave energy stability, energy level occurrence, and variability in the occurrence of effective significant wave height (SWH). The medium- to long-term prediction of wave energy should also synthetically consider the above factors. We conclude that monitoring the propagation of swell energy and calculating the swell index constitutes a robust theoretical basis for predicting the WPD of mixed wave.

73 citations


Book ChapterDOI
01 Jan 2017
TL;DR: In this article, the wave energy resource can be defined by its temporal, directional and spectral characteristics, although many representations of wave energy resources result in the removal of this information, with a consequential distortion of the apparent resource.
Abstract: Understanding the hydrodynamics of waves and the wave energy resource is fundamental to the good design of wave energy converters. The wave energy resource can be defined by its temporal, directional and spectral characteristics, although many representations of the wave energy resource result in the removal of this information, with a consequential distortion of the apparent resource. This chapter discusses how wave energy resource data may be generated using numerical model and validated using site measurements. The chapter also discusses the processes that afffect wave propagation and lead to wave transformation. In its totality, the chapter provides sufficient details of the wave resource to allow an assessment of any particular wave resource assessment to be made, together wtith its potential impact on the performance of a wave energy converter.

63 citations


Journal ArticleDOI
TL;DR: In this paper, the authors presented an assessment of wave energy resources in the Red Sea using numerical modelling, and the wave conditions were simulated for 1979 to 2010 using a third generation ocean wave model, WAVE-III by forcing with CFSR winds.

59 citations


Journal ArticleDOI
TL;DR: In this paper, the analysis of spatiotemporal variability of the Black Sea wave climate from 1979 to 2015 was performed based on mathematical modeling using the modern DHI MIKE 21 SW spectral wave model.

57 citations


Journal ArticleDOI
TL;DR: In this paper, a fine-resolution numerical wave model is used to provide results for the Greek coastal regions and the results deliver the energy potential, variability, and site characterisation for the Aegean Sea.

55 citations


Journal Article
01 Jan 2017-Nature

53 citations


Journal ArticleDOI
01 Feb 2017-Energy
TL;DR: In this article, uncertainties in determining the offshore wind and wave energies were considered to estimate the wind energy potentials in the southern Caspian Sea, and the results showed that uncertainty analysis results in almost 9% lower average wave power density and 7.3% less exploitable energy than conventional analysis.

Journal ArticleDOI
TL;DR: In this article, an unusually long lasting (≳10 days) ultra-relativistic electron flux depletion occurred in the outer radiation belt despite ongoing solar wind forcing.
Abstract: In September 2014 an unusually long lasting (≳10 days) ultra-relativistic electron flux depletion occurred in the outer radiation belt despite ongoing solar wind forcing. We simulate this period using a ULF wave radial diffusion model, driven by observed ULF wave power coupled to flux variations at the outer boundary at L* = 5, including empirical electron loss models due to chorus and hiss wave scattering. Our results show that unexplained rapid main phase loss, that depletes the belt within hours, is essential to explain the observations. Such ultra-relativistic electron extinction decouples the pre- and post-storm flux, revealing the subsequent belt dynamics to be surprisingly independent of pre-storm flux. However, once this extinction is included ULF wave transport and coupling to the outer boundary explain the extended depletion event, and also the eventual flux recovery. Neither local acceleration nor ongoing losses from hiss or chorus wave scattering to the atmosphere are required.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the wave energy potential in the Black Sea based on long-term model simulations and provided information on the longterm variability as well as on the annual, seasonal and monthly averages.

Journal ArticleDOI
TL;DR: This paper focuses on the implementation of a novel MPPT control approach for the OWC systems in order to optimize the power delivered to the grid and successfully matches the optimum rotational speed, allowing maximum active power generation.
Abstract: After the 2015 United Nations Climate Change Conference (COP21) the interest for clean and renewable energy is high priority in global energy policy. In this sense, the ocean offers a great potential for energy harnessing. However, in the path to commercialization, conversion systems still lack maturity. Oscillating water column (OWC) power plants are among the most promising cost-effective and ecologically compatible technologies. The NEREIDA MOWC wave power plant, located on the Basque coast of Mutriku, is a clear example of this principle. In addition, the maximum power point tracking (MPPT) strategy, which has already been used successfully in other renewable energy systems, stands out as one of the most useful schemes. In this context, this paper focuses on the implementation of a novel MPPT control approach for the OWC systems in order to optimize the power delivered to the grid. For this purpose, a full wave-to-wire plant model is introduced, and a new MPPT-based control scheme is presented. The controller continuously adjusts the energy conversion of the doubly fed induction generator according to an established MPPT curve so as to optimize the power generated. In order to demonstrate the goodness and feasibility of the proposed control scheme, its behavior is tested and compared in two representative case studies of both uncontrolled and controlled plants. In the first case, an air valve control is employed, and in the second case, an MPPT-based control strategy has been implemented. Results show that the proposed MPPT-based control successfully matches the optimum rotational speed, allowing maximum active power generation.

Journal ArticleDOI
TL;DR: In this article, the authors explored the wave energy assessment in the northern Persian Gulf taking into account the temporal and spatial distributions of wave power, and the optimal locations for further assessment were determined in the western and southern sides of the southwestern corner of the domain, i.e. Boushehr and Asalouyeh, respectively.

Journal ArticleDOI
TL;DR: In this paper, the authors evaluated the strategic effectiveness of wave and offshore wind energy in the Maldives by using a 10-year hindcast dataset and found that the annual offshore wave power was found to range between 8.46 kW/m and 12.75 kW/M, while the 10 m and 100 m mean wind power density is respectively 0.08 kW /m2 and 0.16 kW / m2.
Abstract: The Maldives are situated in the remote equatorial Indian Ocean, covering 900 km from north to south. The 26 coral atolls forming the archipelago are composed of sand and coral with a maximum height of about 2.30 m above the mean sea level. Periodic flooding from storm surges and the frequent freshwater scarcity are perceived by the population and the economic operators as the major environmental stresses. Moreover, the strong dependence on imported fossil fuels increases, even more, the environmental concerns. Diesel, in fact, still represents the main source of power generation, typically through privately managed small diesel sets. The real challenge for this area is to promote the environmental quality with socioeconomic growth. The present study aims to evaluate the strategic effectiveness to face these issues by wave and offshore wind energy. Resources using a 10-year hindcast dataset are here examined. The annual offshore wave power was found to range between 8.46 kW/m and 12.75 kW/m, while the 10 m and 100 m mean wind power density is respectively 0.08 kW/m2 and 0.16 kW/m2. Based on these results, an environmentally and socio-economically sustainable best-case scenario is constructed and two atoll islands (Male and Magoodhoo) are specifically investigated. As a result, multifunctional structures and multi-use systems, which combine power generation, desalinization and coastal defence, are strongly recommended.

Journal ArticleDOI
11 Aug 2017
TL;DR: This paper presents techno–economic summaries of ocean wave, tidal and current, ocean thermal, and geothermal energy, including grid interface characteristics, suggesting these forms of energy represent a significant opportunity to complement diversified energy conversion portfolios.
Abstract: This paper presents techno–economic summaries of ocean wave, tidal and current, ocean thermal, and geothermal energy, including grid interface characteristics. These forms of energy represent a significant opportunity to complement diversified energy conversion portfolios. Ocean wave energy conversion relies on the capture of kinetic and potential energy in moving and elevated water in an ocean wave. Tidal and current technology converts the kinetic energy in moving water, much like a wind turbine. Ocean thermal converts the energy available in the temperature gradient of warm surface water and cold deep water. Last, geothermal conversion utilizes the hot rock and water deep within the Earth. The total global average wave resource is estimated at approximately 2000 GW, with approximately 300 GW in the United States. The total global tidal resource is estimated at approximately 1000 GW, with 50 GW in the United States. The marine current resource estimate for the Florida Current in the southeast United States is estimated at 5 GW. Ocean thermal has a global capacity estimate of 5000 GW. Last, the global conventional hydrothermal geothermal capacity estimate is approximately 200 GW, but with much more possible through enhanced geothermal systems. For cost, it was found that the long-term projected wave energy conversion cost is $0.10–0.15/kWh. The long-term projected tidal cost is found to be $0.025–0.25/kWh. Ocean thermal long-term cost is projected at $0.10–0.18/kWh. And last, geothermal, being more closely aligned with traditional thermal generation, is estimated at $0.03/kWh to $0.15/kWh.

Journal ArticleDOI
TL;DR: For the first time at Mars the statistical distribution of (1D) electric field wave power in the magnetosphere is presented, along with the distribution of magnetic field wave powers, as observed by the Mars Atmosphere and Volatile EvolutioN spacecraft from the first 14.5 months of the mission as discussed by the authors.
Abstract: For the first time at Mars the statistical distribution of (1D) electric field wave power in the magnetosphere is presented, along with the distribution of magnetic field wave power, as observed by the Mars Atmosphere and Volatile EvolutioN spacecraft from the first 14.5 months of the mission. Wave power in several different frequency bands was investigated and the strongest wave powers were observed at the lowest frequencies. The presented statistical studies suggest that the full thermalization of ions within the magnetosheath does not appear to occur, as has been predicted by previous studies. Manual inspection of 140 periapsis passes on the dayside shows that Poynting fluxes (at 2-16 Hz) between ∼10-11 and 10-8 Wm-2 reach the upper ionosphere for all 140 cases. Wave power is not observed in the ionosphere for integrated electron densities greater than 1010.8 cm-2, corresponding to typical depths of 100-200 km. The observations presented support previous suggestions that energy from the Mars-solar wind interaction can propagate into the upper ionosphere and may provide an ionospheric heating source. Upstream of the shock, the orientation of the solar wind interplanetary magnetic field (IMF) was shown to significantly affect the statistical distribution of wave power, based on whether the spacecraft was likely magnetically connected to the shock or not - something that is predicted, but has not been quantitatively shown at Mars before. In flight performance and caveats of the Langmuir Probe and Waves (LPW) electric field power spectra are also discussed.

Journal ArticleDOI
01 Sep 2017-Energy
TL;DR: In this paper, the authors evaluated nearshore wind and wave climates and their potential as renewable energy sources by means of buoy observational data for the Shenzhen coastal region, and concluded that the potential of wave energy as a renewable resource at the buoy locations was very small.

Journal ArticleDOI
TL;DR: The pendulum wave energy converter (Pendulum Wave Energy Converter) as discussed by the authors is a pendulum-based WEC for the Mediterranean Sea where waves are shorter, thus with a higher frequency compared to the ocean waves, a characteristic well agreeing with the pendulum frequency response.
Abstract: Wave Energy is a widespread, reliable renewable energy source. The early study on Wave Energy dates back in the 70’s, with a particular effort in the last and present decade to make Wave Energy Converters (WECs) more profitable and predictable. The PeWEC (Pendulum Wave Energy Converter) is a pendulum-based WEC. The research activities described in the present work aim to develop a pendulum converter for the Mediterranean Sea, where waves are shorter, thus with a higher frequency compared to the ocean waves, a characteristic well agreeing with the PeWEC frequency response. The mechanical equations of the device are developed and coupled with the hydrodynamic Cummins equation. The work deals with the design and experimental tank test of a 1:12 scale prototype. The experimental data recorded during the testing campaign are used to validate the numerical model previously described. The numerical model proved to be in good agreement with the experiments.

Journal ArticleDOI
TL;DR: In this paper, a long-term hindcast for the Scottish coastlines run from 2004 to 2014 (11 years) improving the existing wave maps and resource estimations is presented, underlining the importance of resource assessment and attempts to improve the quantifiable wave power resource with use of a validated numerical model.

Journal ArticleDOI
TL;DR: In this article, a test bed study conducted to evaluate best practices in wave modeling to characterize energy resources is presented, where two third-generation spectral wave models, SWAN and WWIII, were evaluated.

Journal ArticleDOI
TL;DR: In this article, a fundamental investigation into the wave power capture capacity of two interconnected floats with arbitrary float length is presented, which enables the authors to carry out a frequency-domain analysis.

Journal ArticleDOI
TL;DR: In this article, the authors analyzed how changes in wave patterns, due to the effect of climate change, can affect wave energy power and yield around Menorca (NW Mediterranean Sea).

Journal ArticleDOI
TL;DR: In this paper, a series of wave-flume experiments was conducted to examine the hydrodynamic performance of a rectangular OWC device fixed in regular waves, and two types of orifices were used to simulate the nonlinear power take-off (PTO) mechanism, and the effects of orifice geometry were examined.
Abstract: Oscillating water column (OWC) devices for wave power extraction are appealing, but are still in need of research. In this study, a series of wave-flume experiments was conducted to examine the hydrodynamic performance of a rectangular OWC device fixed in regular waves. Two types of orifices, slot orifices and circular orifices, were used to simulate the nonlinear power take-off (PTO) mechanism, and the effects of orifice geometry were examined. A two-point measurement method was proposed to reconstruct the instantaneous spatial profile of the water surface inside the OWC chamber for reducing bias in the measured wave power extraction efficiency. The flow characteristics of PTO were described by a quadratic loss coefficient, and our experimental results showed that the quadratic loss coefficient of the slot orifices varied with wave period and slot geometry. Empirical formulas were proposed for the quadratic loss coefficients of the two types of orifices. The ability to determine the quadratic loss coefficient of an orifice will allow us to design orifices for small-scale tests and calculate the power extraction using only pressure measurement. Our results also suggested that the pressure coefficient should be more reliable than the amplification coefficient as an indicator of the power extraction performance of an OWC device.

Journal ArticleDOI
TL;DR: In this paper, the authors describe the preliminary developments of an innovative integrated tool for the numerical modelling of oscillating water column (OWC) wave energy converters (WEC) integrated in vertical breakwaters.

Journal ArticleDOI
TL;DR: In this article, the numerical code to generate waves in a 3D Numerical Wave Tank (NWT) is first validated against experimental data to check the accuracy and robustness of the code.

Journal ArticleDOI
TL;DR: In this paper, the authors assessed the predictability of available global offshore wind and wave power for lead times of up to 9 days using a state-of-the-art wave model and a six-member multi-model ensemble of operational numerical weather predictions during the boreal summer and winter for the period 2008-2012.

Journal ArticleDOI
TL;DR: In this article, the authors present an assessment of the wave energy resource in nearshore waters along the central coast of Chile (Lat.:32.5°S to 42°S) using hindcast and measured data collected specifically for this goal.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated whether deploying arrays of devices across multiple spatially separated sites can reduce intermittency of supply and step changes in generated power, thereby smoothing the contribution of wave energy to power supply.