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Favourable land formations in places with large differential tide heights can cause fast flowing tidal streams. One such tidal stream in the Northern Territory, with power densities as high as 6 kW/m^2 , is the site of a kinetic tidal generator project. This paper presents the development of a high efficiency tidal generator to harness the kinetic...
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... high in capital cost. This is especially true of wind and kinetic tidal generators due to the size of the turbines and the mechanical structures required to support them. For this reason it is vitally important to harness as much of the energy passing through the turbine as possible by making all stages of the conversion system highly efficient. Fig. 3 shows a block diagram of a wind or kinetic tidal generator system showing the power sections including the system controller, if one is used. There is much pressure on engineers to increase the efficiency of all components including the turbine, the gearbox(es), the generator and the controller, and to implement a control system to ...
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... The study intended to showcase the practi-cal aspects of the turbines' implementations, performances, efficiencies, reliabilities and problems encountered. For instance, the case study in Australia evaluated the performance of small axial flow turbines for the Nguiu community in Apsley Strait to replace the use of diesel fuel [43]. The works of Chihaia [15] also give a detailed review and present the works of numerous case studies performed by researchers from the inception of the technology conducted in Brazil until the concept's acceptance in Indonesia. ...
Energy accessibility, reliability and availability are key components of improved quality of life and human development in all spheres. As the United Nations’ SDG 7 calls for access to electricity for all by 2030, Africa still has a wide gap to fill as the statistics show that 85% of the population that will not have access to electricity is in Africa. As the world tries to wean itself off non-renewable energy and transition to green through use of renewable energy sources, hydropower energy remains at the heart of Africa for this venture. With majority of the rural population in Africa lacking electricity, there is need for a low-tech system that utilizes river flow to generate just enough energy for normal operation in these regions. Micro-hydrokinetic river turbine technology (µ-HRT), which offers less intermittency, can potentially contribute to sustainably electrifying Africa rural areas. The technology has been adopted by few countries worldwide, with limited comprehensive study in Africa even though the technology seems viable for use in African rivers. This paper reviewed the status of the µ-HRT applications in Africa and some of the barriers to its development. The study found out that the technology has not been vastly developed in Africa. Despite numerous barriers, the technology is simply a low-tech technology that requires the use of local resources and capacity building for its sustainability in terms of construction, operation and maintenance requirements. It is therefore recommended that R&D and field trials be conducted for its possible adoption.
... A valuable piece of literature on controller synthesis and maximum power extraction of a small propeller type tidal turbine is found in [29]. In this work, Tip Speed Ratio (TSR) of a turbine is assessed and a PID type controller was used to control a dump load and achie maximum power output. ...
River Current Turbines are electromechanical energy converters that convert kinetic energy of river water into other usable forms of energy. Over the last few decades, a number of reports on technical and economic feasibility of this technology have emerged. However, the potentials of this technology as an effective source of alternative energy has not yet been explored to a great extent. The underlying challenges of system design, operation and economics also lack proper understanding. In this article, starting with a definition of the River Current Turbines, an overview of the technological advancements in the relevant field is provided. From a system engineering perspective , various merits and prospects of this technology along with pertinent challenges are discussed. The cross-disciplinary nature of approaching these challenges with an emphasis on the need for contributions from electrical engineering domain are also outlined in brief. This article may serve as a coherent literature survey or technology review that would provide better understanding of the subjacent issues and possibly rejuvenate research interest in this immensely potential field of energy engineering.
... Besides, they do not require additional civil works, thereby reducing costs and favoring their versatility [124,126,127,[131][132][133]. However, WCTs present problems and interferences with weed (e.g., water hyacinth) and floating debris [134][135][136][137][138][139], which in turn determine their maintenance frequency, though this largely depends on the type of river [140]. There are cases of turbines cleaned several times a day [124], and other ones only every few days or weeks [140,141]. ...
Water pumping systems driven by renewable energies are more environmentally sound and, at times, less expensive alternatives to electric- or diesel-based ones. From these, hydro-powered pumps have further advantages. Nevertheless, these seem to be largely ignored nowadays. More than 800 scientific and nonscientific documents contributed to assemble their fragmented storylines. A total of 30 pressure-based hydro-powered pumping technologies worldwide have been classified and plotted in space and time. Although these do not present identifiable patterns, some noticeable clusters appear in regions such as Europe, South–Southeast Asia, and Eastern Africa, and in timeframes around 1960–1990, respectively. Some technologies have had a global impact and interest from their beginnings until contemporary times, others have been crucial for the development of specific countries, and other ones barely had almost imperceptible lives. All of them, nonetheless, have demonstrated to be a sound alternative to conventional pumping technologies, which can be unaffordable or inaccessible, particularly in remote and off-the-grid areas. Currently, hydro-powered pumping technologies face a regained momentum, hence a potentially promising future. However, researchers, manufacturers, and users need to be aware of the importance that management systems, as well as business models, pose for these technologies beyond their mere performance.
... The evaluation of small axial flow turbines performance intended to generate electricity for Nguiu community in Apsley Strait, to replace the use of diesel fuel, was performed by Tuckey et al. [13] and Swenson [14]. In their work, the performance of two different types of turbines was compared. ...
Micro-hydrokinetic turbine (μ-HKT) technology is considered a viable option for sustainable, green and low cost power production. In recent years, there is growing number of research and development on this technology to replace conventional power production systems such as fossil fuel as well as to provide off-grid electrification to communities in remote areas. This paper provides an overview of μ-HKT system, the implementation of the technology and the potential of using μ-HKT in Malaysia. A review on the climate in Malaysia shows that its average annual rainfall is higher than the world's average annual rainfall. It contributes to the total hydropower resource of about 29,000 MW which is available all year-round. Currently, hydropower resource contributes only 7.4% of the total electrical power production in Malaysia but is expected to increase with the main contribution coming from μ-HKT. However, the μ-HKT technology has not been adopted in Malaysia due to some challenges that hinder the development of the system. This paper reviews the μ-HKT technology and its potential for application in Malaysia, particularly in remote areas.
... Perhaps some of the most transparent field trial reports on small axial flow turbines intended for remote application were published by the Northern Territory University (NTU), Australia, now Charles Darwin University (Swenson, 1996(Swenson, , 1999Tuckey et al., 1997). This effort was carried out to gauge the possibility of generating electricity for Nguiu community in Apsley Strait using hydrokinetic turbines in order to displace the use of diesel fuel there. ...
This paper reviews works involving small axial flow hydrokinetic turbines specifically for generating electrical power for off-grid remote communities and suggests improvements to overcome a major problem. Turbines mounted on pontoons or suspended using pivot arms from river banks or from jetties are reported able to produce about 1kW to 2kW of electrical power suitable for remote homes. However several deployments have experienced major problems with debris attaching to the turbines, resulting in interrupted operation. Excessive work in removing debris and furling result in frequent power cuts, a disadvantage in systems supplying AC power on demand, and this problem impedes the acceptance of hydrokinetic turbines in remote community electrification. Some methods of dealing with the debris problem have been suggested but these all involve interrupted operation. A system using a rotor with swept-back blades is suggested, where debris is shed automatically without lifting the turbine out of water. A deflecting device could also be used to push floating logs away from the swept area. By making the system resistant to debris, efficient axial flow turbines could be used practically in tropical rivers. Accessibility to power enables the use of basic home appliances and to encourage small village industries which can help to improve their socio-economic standard.
... Turbines with solid mooring structures require the generator unit to be placed near the riverbed or seafloor . Reports and information on rigidly moored tidal/river turbines are available in [22,34,5152535455. Horizontal axis rotors with a buoyant mooring mechanism may allow a non-submerged generator to be placed closer to the water surface. ...
The energy in flowing river streams, tidal currents or other artificial water channels is being considered as viable source of renewable power. Hydrokinetic conversion systems, albeit mostly at its early stage of development, may appear suitable in harnessing energy from such renewable resources. A number of resource quantization and demonstrations have been conducted throughout the world and it is believed that both in-land water resources and offshore ocean energy sector will benefit from this technology. In this paper, starting with a set of basic definitions pertaining to this technology, a review of the existing and upcoming conversion schemes, and their fields of applications are outlined. Based on a comprehensive survey of various hydrokinetic systems reported to date, general trends in system design, duct augmentation, and placement methods are deduced. A detailed assessment of various turbine systems (horizontal and vertical axis), along with their classification and qualitative comparison, is presented. In addition, the progression of technological advancements tracing several decades of R&D efforts are highlighted.
... A valuable piece of literature on controller synthesis and maximum power extraction of a small propeller type tidal turbine is found in [29]. In this work, Tip Speed Ratio (TSR) of a turbine is assessed and a PID type controller was used to control a dump load and achieve maximum power output. ...
River current energy conversion systems (RCECS) are electromechanical energy converters that convert kinetic energy of river water into other usable forms of energy. Over the last few decades, a number of reports on technical and economic feasibility of this technology have emerged. However, the potentials of this technology as an effective source of alternative energy have not yet been explored to a great extent. The underlying challenges of system design, operation and economics also lack proper understanding. In this article, starting with a definition of the RCECS, an overview of the technological advancements in the relevant field is provided. From a system engineering perspective, various merits and prospects of this technology along with pertinent challenges are discussed. The cross-disciplinary nature of approaching these challenges with an emphasis on the need for contributions from various technical and non-technical domains are also outlined in brief. This article may serve as a coherent literature survey or technology review that would provide better understanding of the subjacent issues and possibly rejuvenate research interest in this immensely potential field of energy engineering.
... Many energy harvesting mechanisms resemble the driven damped harmonic oscillator (DDHO), which is formed by an oscillating mass and an energy generation mechanism which dampens the motion of the mass [3]. Another example of the DDHO energy harvesting system is the ocean wave energy harvesting buoys, which are driven by the periodic motion of the waves [4,5]. Recent work has also been done on the harvesting of energy from small vibrating oscillators [6]. ...
This paper presents an optimal method of designing and controlling an oscillating energy harvesting system. Many new and emerging energy harvesting systems, such as the energy harvesting backpack and ocean wave energy harvesting, capture energy normally expelled through mechanical interactions. Often the nature of the system indicates slow system time constants and unsteady AC voltages. This paper reveals a method for achieving maximum energy harvesting from such sources with fast determination of the optimal operating condition. An energy harvesting backpack, which captures energy from the interaction between the user and the spring decoupled load, is presented in this paper. The new control strategy, maximum energy harvesting control (MEHC), is developed and applied to the energy harvesting backpack system to evaluate the improvement of the MEHC over the basic maximum power point tracking algorithm.
... Turbines with solid mooring structure require the generator unit to be placed near the river or seabed. Reports and information on rigidly moored tidal/river turbines are available in [11]- [17]. Horizontal axis rotors with a buoyant mooring mechanism may allow a non-submerged generator placed closer to the water surface. ...
Hydrokinetic turbines convert kinetic energy of moving river or tide water into electrical energy. In this work, design considerations of river current turbines are discussed with emphasis on straight bladed Darrieus rotors. Fluid dynamic analysis is carried out to predict the performance of the rotor. Discussions on a broad range of physical and operational conditions that may impact the design scenario are also presented. In addition, a systematic design procedure along with supporting information that would aid various decision making steps are outlined and illustrated by a design example. Finally, the scope for further work is highlighted
... Turbines with solid mooring structure require the generator unit to be placed near the river or seabed. Reports and information on rigidly moored tidal/river turbines are available in [11][12][13][14][15][16][17]. Horizontal axis rotors with a buoyant mooring mechanism may allow a non-submerged generator to be placed closer to the water surface. ...
River current turbines are electromechanical energy converters that harness kinetic energy of a stream of flowing river water to generate electricity. Research in this domain is limited and various concepts are emerging only recently. In this paper, an extensive technology survey and comparison of various system options are discussed in order to formulate a basis for further analysis. Simplified mathematical modeling of an augmentation device and Darrieus type rotor has been carried out. Simulations are done in Matlab and results are given with graphical interpretations. In conclusion, directions for further investigation are given and the potential of this technology is re-stressed
