Tidal Current Energy for Indian Coastal Lines ─ A State Art of Review
01 Dec 2020-Vol. 1716, Iss: 1, pp 012008
About: The article was published on 2020-12-01 and is currently open access. It has received 2 citations till now.
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TL;DR: In this paper , the authors examined turbine wake properties to offer a basic framework for the exploration of turbine arrangements through the OpenFOAM source package and the entropy production theory, showing that the diffuser inlet produces the largest entropy rate.
Abstract: An implication of a turbine current is the development of a wake, a reduced speed flow, thus affecting the performance of an adjoined turbine. The aim of this study is to examine the turbine wake properties to offer a basic framework for the exploration of efficient turbine arrangements through the OpenFOAM source package and the entropy production theory. The results indicate that the diffuser inlet produces the largest entropy rate; however, this dissipates quickly after the rotor plane. In terms of vorticity, the Q and λ2-criterion results are sensitive to the isosurface thresholds. In general, the Ω-Rortex method proves a convenient and accurate solution for vortex visualization and identification. For the overall mean wake structure, the velocity profile follows a tadpole-shape, whilst the velocity deficits above 100% are observed around the nacelle and throat (diffuser) and behind the tower. The concentration of maximum turbulent intensities appears behind the throat of the diffuser and at the top and bottom of the tower. Owing to the swirling effect after rotor, we proposed recommended values of b0 = 10−5 for the hydrodynamic investigation of tidal stream turbines. The present findings extend our knowledge on the flow disruption due to shrouded turbines and are particularly relevant for farm project advisors.
6 citations
TL;DR: In this article , the authors used UAV imagery to quantify the density distribution of pursuit-diving seabirds, called auks (of the family Alcidae), distribution in comparison relation to concurrent surface imagery of kolk-boils and, analyse evaluate spatial relationships with individual kolkboil features, and quantify body orientation relative to the water flow.
Abstract: Tidal stream environments exhibit fast current flows and unique turbulent features occurring at fine spatio-temporal scales (metres and seconds). There is now global recognition of the importance of tidal stream environments for marine megafauna. Such areas are also key to the development of marine renewable energy due to the reliable and predictable nature of tidally driven flows. Bed-derived turbulent features, such as kolk-boils, transport organic material to the surface and may increase the availability of prey species (fish) for foraging marine megafauna (seabirds and marine mammals). Quantification of animal association and interactions with turbulent features is required to understand potential environmental impacts of tidal energy developments in these sites. Downward-facing unmanned aerial vehicle (UAV) imagery was collected within the Pentland Firth, UK. Resulting imagery was used to quantify the density distribution of pursuit-diving seabirds, called auks (of the family Alcidae), distribution in comparison relation to concurrent surface imagery of kolk-boils and, analyse evaluate spatial relationships with individual kolk-boil features, and quantify body orientation relative to the water flow. Although variability was present, auk density distribution was generally correlated with that of kolk-boils throughout the study area; however, spatial analysis highlighted an overall trend of finer-scale dispersion between individual auks and kolk-boils. Auk orientation on the surface was primarily observed across the flow throughout ebb and flood tidal phases. These results suggest that auks may be associating with kolk-boil peripheries. Similarly, it may be energetically beneficial to orientate across the flow while maintaining observation of current flow or searching for shallow prey species and potential threats in the environment. This work demonstrates that UAV imagery was appropriate for quantification of fine-scale biophysical interactions. It allowed for concurrent measurement of hydrodynamic and predator metrics in a challenging environment and provided novel insights not possible to collect by conventional survey methodology. This technique can increase the evidence base for assessment of potential impacts of marine renewable energy extraction on key marine species.
2 citations
References
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TL;DR: Tidal energy has the potential to play a valuable part in a sustainable energy future and is an extremely predictable energy source, depending only on the gravitational pull of the moon and the sun and the centrifugal forces created by the rotation of the earth-moon system as discussed by the authors.
433 citations
TL;DR: In this article, a step-by-step approach for wave and marine current ocean energy conversion is presented, depicting results based on experimental and field observations on device fundamentals, modelling approaches, project development issues.
Abstract: Ocean energy has many forms, encompassing tides, surface waves, ocean circulation, salinity and thermal gradients. This paper will considers two of these, namely those found in the kinetic energy resource in tidal streams or marine currents, driven by gravitational effects, and the resources in wind-driven waves, derived ultimately from solar energy. There is growing interest around the world in the utilisation of wave energy and marine currents (tidal stream) for the generation of electrical power. Marine currents are predictable and could be utilised without the need for barrages and the impounding of water, whilst wave energy is inherently less predictable, being a consequence of wind energy. The conversion of these resources into sustainable electrical power offers immense opportunities to nations endowed with such resources and this work is partially aimed at addressing such prospects. The research presented conveys the current status of wave and marine current energy conversion technologies addressing issues related to their infancy (only a handful being at the commercial prototype stage) as compared to others such offshore wind. The work establishes a step-by-step approach that could be used in technology and project development, depicting results based on experimental and field observations on device fundamentals, modelling approaches, project development issues. It includes analysis of the various pathways and approaches needed for technology and device or converter deployment issues. As most technology developments are currently UK based, the paper also discusses the UK's financial mechanisms available to support this area of renewable energy, highlighting the needed economic approaches in technology development phases. Examination of future prospects for wave and marine current ocean energy technologies are also discussed.
341 citations
TL;DR: In this article, a detailed up-to-date description of the current status of development of marine current energy devices (MCEDs) in Ireland is presented. But, it is still not economically viable on a large scale due to its current stage of development.
Abstract: There is a growing demand for the use of renewable energy technologies to generate electricity due to concerns over climate change. The oceans provide a huge potential resource of energy. Energy extraction using marine current energy devices (MCEDs) offers a sustainable alternative to conventional sources and a predictable alternative to other renewable energy technologies. A MCED utilises the kinetic energy of the tides as opposed to the potential energy which is utilised by a tidal barrage. Over the past decade MCEDs have become an increasingly popular method of energy extraction. However, marine current energy technology is still not economically viable on a large scale due to its current stage of development. Ireland has an excellent marine current energy resource as it is an island nation and experiences excellent marine current flows. This paper reviews marine current energy devices, including a detailed up-to-date description of the current status of development. Issues such as network integration, economics, and environmental implications are addressed as well as the application and costs of MCEDs in Ireland.
204 citations
TL;DR: Tidal barrages are typically a dam, built across a bay or estuary that experiences a tidal range in excess of 5 m as mentioned in this paper, where turbines, sluice gates, embankments and ship locks are used to generate electricity.
47 citations
TL;DR: In this paper, a review of the existing tidal energy harnessing systems is presented and the challenges and practical solutions for each basic structure of the tidal harnessing system are compared and discussed.
Abstract: With the increasing concern of global warming, the importance of reducing greenhouse gas emissions has been accepted worldwide. Realizing the contribution of conventional energy sources to greenhouse gas emissions and the increasing demand for energy, the harnessing of renewable energy is becoming an important issue in our time. As a renewable source, tidal energy is coming into consideration recently because of its long term predictability and large potential. In this paper, the existing tidal energy harnessing systems are reviewed and the challenges and practical solutions for each basic structure of the tidal harnessing system are compared and discussed. The Gulf Stream and North Carolina tidal water properties are investigated. Based on the review and discussion of existing devices, suitable harnessing devices for Gulf Stream and North Carolina tidal water are proposed.
36 citations