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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
571

Energy Storage Solutions for Wind Generator Connected Distribution Systems in Rural Ontario

Rahman, Mohammed Nahid January 2009 (has links)
Environmental awareness and uncertainty about continued supply of fossil fuel has given rise to the renewable energy movement. Wind based power generation has been at the forefront of the motion to integrate distributed energy sources in the traditional power system. Due to various technical restrictions, wide scale penetration of wind generated power has been held back by most utilities. One such restriction is the variability of generation due to the technology’s dependence on Mother Nature. Energy storage devices can complement the wind generators by reducing this variability. These devices can store excess generation for supply during low generation periods. There are several promising technologies for both energy storage and power storage applications. Power storage devices provide short term fluctuation dampening capability while energy storage devices allow longer term storage. Pumped hydro, Vanadium Redox battery and Sodium-Sulphur battery are some of the viable energy storage technologies. This project provides a set of algorithms and guidelines to obtain the optimal configuration parameters of an energy storage device. To verify the efficiency of the algorithms, a model system has been obtained from a local utility. This system represents a typical radial distribution system in rural Ontario. The load demand, wind speed and energy prices for a period of one year have been obtained from utilities and Environment Canada. The main goal in determining the location of the storage device within a distribution system is to minimize the total cost of energy and the total energy loss during the period of analysis. Locating the storage device near the wind turbines or near the largest loads lead to the optimum results. Buses that are located near those elements can be considered as suitable locations for the storage device. The energy storage capacity and charge-discharge rate of the storage device are selected based on four criteria: maximize wind turbines’ load following capability, maximize capacity factors of the wind turbines, minimize system energy losses and minimize system energy costs. A weight based multi-objective optimization algorithm has been proposed to assign various priorities to these criteria and obtain a single solution. The larger the energy storage capacity of the storage device, the better the improvement in system performance. Lower charge-discharge ramp rates provide superior results. The parameters for storage device operating schedule, i.e. charge-discharge trigger levels, have been selected using similar criteria and weighted objective approach as for the capacity selection process. Higher charge trigger levels and moderate discharge trigger levels provide the optimum system performance. Once a set of parameters for the storage device has been selected, bus voltages over the period of study are analyzed. Voltage variations outside certain limits have been identified. Finally, a Monte Carlo based simulation approach is presented to obtain output parameter (system performance) variation ranges for pseudo random changes in input parameters.
572

On Techno-economic Evaluation of Wind-based DG

Albadi, Mohammed 21 January 2010 (has links)
The growing interest in small-scale electricity generation located near customers, known as Distributed Generation (DG), is driven primarily by emerging technologies, environmental regulations and concerns, electricity market restructuring, and growing customer demand for increased quality and reliability of the electricity supply. Wind turbines are one of the renewable DG technologies that have become an important source of electricity in many parts of the world. Wind power can be used in many places to provide a viable solution to rising demand, energy security and independence, and climate change mitigation. This research aims broadly at facilitating the integration of wind-based DG without jeopardizing the system’s economics and reliability. To achieve this goal, the thesis tackles wind power from three perspectives: those of the policy maker, the investor, and the system operator. Generally, the economic viability of a project is determined within the framework of relevant policies. Therefore, these policies influence the decisions of potential investors in wind power. From this perspective, chapters 3 and 4 investigate the influence of policies on the economic viability of wind-based DG projects. In chapter 3, the role of Ontario’s taxation and incentive policies in the economic viability of wind-based DG projects is investigated. In this study, the effects of provincial income taxes, capital cost allowances, property taxes, and relevant federal incentives are considered. Net Present Value (NPV) and Internal Rate of Return (IRR) for different scenarios are used to assess the project’s viability under the Ontario Standard Offer Program (SOP) for wind power. In chapter 4, the thesis proposes the use of wind power as a source of electricity in a new city being developed in the Duqm area of Oman, where no policies supporting renewable energy exist. The study shows that the cost of electricity produced by wind turbines is higher than that of the existing generation system, due to the subsidized prices of domestically available natural gas. However, given high international natural gas prices, the country’s long-term Liquefied Natural Gas (LNG) export obligations, and the expansion of natural gas-based industries, investments in wind power in Duqm can be justified. A feed-in tariff and capital cost allowance policies are recommended to facilitate investments in this sector. From a wind-based DG investor’s perspective, the optimal selection of wind turbines can make wind power more economical, as illustrated in chapters 5 and 6. In chapter 5, the thesis presents a new generic model for Capacity Factor (CF) estimation using wind speed characteristics at any site and the power performance curve parameters of any pitch-regulated wind turbine. Compared to the existing model, the proposed formulation is simpler and results in more accurate CF estimation. CF models can be used by wind-based DG investors for optimal turbine-site matching applications. However, in chapter 6, the thesis demonstrates that using CF models as the sole basis for turbine-site matching applications tends to produce results that are biased towards higher towers but do not include the associated costs. Therefore, a novel formulation for the turbine-site matching problem, based on a modified CF formulation that does include turbine tower height, is introduced in chapter 6. The proposed universal Turbine-Site Matching Index (TSMI) also includes the effects of turbine rated power and tower height on the initial capital cost of wind turbines. Chapter 7 tackles wind power from a power system operator’s perspective. Despite wind power benefits, the effects of its intermittent nature on power systems need to be carefully examined as penetration levels increase. In this chapter, the thesis investigates the effects of different temporal wind profiles on the scheduling costs of thermal generation units. Two profiles are considered: synoptic-dominated and diurnal-dominated variations of aggregated wind power. To simulate wind profile impacts, a linear mixed-integer unit commitment problem is formulated in a GAMS environment. The uncertainty associated with wind power is represented using a chance constrained formulation. The simulation results illustrate the significant impacts of different wind profiles on fuel saving benefits, startup costs, and wind power curtailments. In addition, the results demonstrate the importance of the wide geographical dispersion of wind power production facilities to minimize the impacts of network constraints on the value of the harvested wind energy and the amount of curtailed energy.
573

Multikriterieanalys för identifiering av lämpliga områden för etablering av vindkraftverk

Söderholm, Emma, Nordsell, Lise-Lott January 2008 (has links)
Idag fokuseras det politiska intresset på klimatfrågor och det visade sig inte minst när Nobels fredpris tilldelades Panel of Climate Change och Al Gore år 2007. Klimatfrågor med fokusering på bland annat energifrågan, biologisk mångfald och hållbar utveckling kommer att vara nyckelfrågor under andra halvan av 2009 när Sverige är ordförandeland för EU. Bidragande orsaker till klimatförändringar är mänskliga utsläpp av växthusgaser. Arbetet med att minska utsläppen sker bland annat genom Kyotoprotokollet, där 160 stater deltar, innehållande bindande åtaganden att minska utsläppen med 5 % fram till 2012. I och med arbetet med att minska växthusgaser är främjandet och utvecklandet av förnyelsebar energi en viktig del, särskilt i form av vindkraft. Kommunernas fysiska planering spelar en viktig roll i detta, t ex i framtagandet av lämpliga områden för etablering av vindkraft. Gävle kommun används som fallstudie och detta arbete ska underlätta förfarandet att ta fram bra beslutsunderlag som varje planerare behöver göra. Syftet med denna studie är att underlätta och effektivisera den fysiska planeringens arbete och väcka medvetenhet för nyttan av GIS. Först sker en sammanställning av en del data som finns tillgängliga på Gävle kommun. Huvudsyftet är att sedan utföra en multikriterieanalys för att hitta lämpliga områden för vindkraftsetablering utifrån sammanställt data. Vindkraft valdes för att det är en viktig del i anpassningsarbetet för att motverka klimatförändringar och har en hög prioritet. Kriterier och motstående intressen till vindkraftsetablering sattes upp och utifrån det utfördes sedan en multikriterieanalys. En fältstudie utfördes för att bedöma resultatets tillförlitlighet och hur resultatet överensstämmer med verkligheten. Resultatet påvisade att det fanns många lämpliga områden för vindkraftsetablering i Gävle kommun och att god överensstämmelse fanns med tidigare framtagna riksintresseområden för vindkraftverk. Fältstudierna visade även på god överensstämmelse med resultatet och verkligheten. Multikriterieanalys är ett kraftfullt verktyg som ger tydliga resultat. Kunskap om metodiken och ämnet, t ex om den ska hitta lämpliga områden för vindkraft krävs god kännedom om vindkraft samt kunskap om data krävs för att metoden ska vara lätt att genomföra. Den ger ett begripligt resultat som har stor genomslagskraft och som det är lätt att ta till sig. Metoden är en väldigt användbar metod för att ta fram bra beslutsunderlag i ett planarbete. / The political focus is today set on questions concerning climate changes and this was proved when Panel of Climate Change and Al Gore were awarded with the Nobel Prize for Peace in the year of 2007. Sweden is the presidency country of the European Union in the second half of 2009 and the main questions are going to be about climate targeted on energy, biodiversity and sustainable development. Some of the things that cause the climate changes are the emission of greenhouse gases made by the human being. To reduce the emission the goal with the Kyoto protocol, accepted by 160 countries, is set to reduce the emission by 5% until 2012. To achieve the goal the development and promoting of renewable energy has an important role, especially wind power. With the aid of physical planning, municipalities have an important role e.g. through compiling basic data for decision-making where suitable areas for wind power are pointed out. Gävle municipality is used as a case study and one of the goals with this thesis is to facilitate the decision that is needed to be made by them who are working with physical planning. Another goal is to awake the awareness of geographical information system potential to be a powerful tool to make physical planning more efficient. As a first part a compilation is made of the data that are accessible in the databases of Gävle municipality. The main issue is to make a multicriteria analysis to find suitable areas for wind power on the compiled data. The theme of wind power was chosen because it is an important part of a sustainable development due to climate changes. Criteria and counteractive interests to wind power were identified and used in a multicriteria analysis. A field study was made to control the result from the multicriteria analysis against reality and there were a good agreement. The result of the multicriteria analysis indicated that there are several suitable areas for wind power within the area of Gävle municipality and this was verified with the areas identified by the County Administration of Gävleborg. Multicriteria analysis is a powerful tool that gives a result that is easy to understand. Knowledge about the method and subject, e.g. finding areas suitable for wind power good knowledge about wind power and data is demanded to make the method easy to perform. The method gives a comprehensible result with a penetrating power and is easy to understand. The method is very useful to compile basic data for decision-making in physical planning.
574

Windmill driven water pump for small-scale irrigation and domestic use : In Lake Victoria basin

Salomonsson, Sara, Thoresson, Helena January 2010 (has links)
This project is a combination of mechanical engineering and sustainable development in developing countries. The goal has been to build a windmill driven water pump and to design a small-scale irrigation system for SCC-Vi Agroforestry’s demonstration farm in Musoma, Mara region, Tanzania. The purpose was to enable SCC-Vi Agroforestry to demonstrate and spread knowledge about these techniques to farmers in the region. In 2007, two students from Halmstad University conducted a field study in the Mara region and found that many farmers lack clean and running water. Back in Sweden they constructed a prototype of a windmill that employs wind energy to pump water using a semi-rotary pump. The intention is that local farmers should be able to build their own windmill, and thus have running water in their household. However, the windmill has never been built in Tanzania. The windmill construction in this report is based on the prototype, but the original drawings were changed to fit the specific situation in Tanzania better. Important throughout the project has been to minimise cost and to only use material that local farmers can get hold of. Building and assembling of the windmill were then performed by the authors in co-operation with local workers. The windmill drives a pump that pumps water from a well to a tank for further use in irrigation. Calculations have been made on the energy available in the wind and an energy analysis was then performed to see what wind speed is required for the system to work. If wind speed is low, the windmill can be adjusted by placing the connecting rod closer to the rotation centre where it requires less work to function. As a result of that, the volume of water per stroke will decrease and it will take longer time to fill the tank. This project was carried out during the rainy season when there is less wind; therefore the windmill has not been tested during optimal wind speed conditions. The tests that have been performed during the circumstances at the time showed that the performance of the windmill is consistent with the theoretical calculations. A proposed design for a simple drip irrigation system has been developed based on the conditions at the project area. It is constructed of plastic pipes with holes that emit water. Covers are in place to prevent soil from clogging the holes. Building the irrigation system was not part of this project.
575

Ekonomiska innovationer i den gotländska vindkraftsindustrin / Sources of funding for the wind power industry on Gotland

Carlzon, Jonathan, Lundborg, Rebecca January 2011 (has links)
Currently there is a controversial debate about that we must reduce our impact on the global warming; therefore both the Government and the local authorities have invested heavily in developing renewable energy in Sweden. The major development on the wind power market can be seen as a result of both the technological development and also on the decision that the Government took in 1996, which opened up the wind power market for private parties. This paper has aimed to examine the types of financial innovations that have arisen from the investments and financing of wind power on Gotland, and what these innovations can contribute to the future development of wind power. The problems that this thesis is based on is; what kind of financial innovations have occurred within investment and financing of wind power? How can these innovations contribute to the continued development of wind power on Gotland? The conclusion of this study shows that respondents and participants have defined a number of financial innovations that have emerged. Where some of the innovations only can be seen as incremental since they are based on continuous improvements, while others can be seen as radical as they are completely new for the context in which they operate. The study has also shown that Gotland has a great potential to produce more renewable electricity, but the development is dependent on the new power lines being built, in order to export electricity to the mainland.
576

Energy Storage Solutions for Wind Generator Connected Distribution Systems in Rural Ontario

Rahman, Mohammed Nahid January 2009 (has links)
Environmental awareness and uncertainty about continued supply of fossil fuel has given rise to the renewable energy movement. Wind based power generation has been at the forefront of the motion to integrate distributed energy sources in the traditional power system. Due to various technical restrictions, wide scale penetration of wind generated power has been held back by most utilities. One such restriction is the variability of generation due to the technology’s dependence on Mother Nature. Energy storage devices can complement the wind generators by reducing this variability. These devices can store excess generation for supply during low generation periods. There are several promising technologies for both energy storage and power storage applications. Power storage devices provide short term fluctuation dampening capability while energy storage devices allow longer term storage. Pumped hydro, Vanadium Redox battery and Sodium-Sulphur battery are some of the viable energy storage technologies. This project provides a set of algorithms and guidelines to obtain the optimal configuration parameters of an energy storage device. To verify the efficiency of the algorithms, a model system has been obtained from a local utility. This system represents a typical radial distribution system in rural Ontario. The load demand, wind speed and energy prices for a period of one year have been obtained from utilities and Environment Canada. The main goal in determining the location of the storage device within a distribution system is to minimize the total cost of energy and the total energy loss during the period of analysis. Locating the storage device near the wind turbines or near the largest loads lead to the optimum results. Buses that are located near those elements can be considered as suitable locations for the storage device. The energy storage capacity and charge-discharge rate of the storage device are selected based on four criteria: maximize wind turbines’ load following capability, maximize capacity factors of the wind turbines, minimize system energy losses and minimize system energy costs. A weight based multi-objective optimization algorithm has been proposed to assign various priorities to these criteria and obtain a single solution. The larger the energy storage capacity of the storage device, the better the improvement in system performance. Lower charge-discharge ramp rates provide superior results. The parameters for storage device operating schedule, i.e. charge-discharge trigger levels, have been selected using similar criteria and weighted objective approach as for the capacity selection process. Higher charge trigger levels and moderate discharge trigger levels provide the optimum system performance. Once a set of parameters for the storage device has been selected, bus voltages over the period of study are analyzed. Voltage variations outside certain limits have been identified. Finally, a Monte Carlo based simulation approach is presented to obtain output parameter (system performance) variation ranges for pseudo random changes in input parameters.
577

On Techno-economic Evaluation of Wind-based DG

Albadi, Mohammed 21 January 2010 (has links)
The growing interest in small-scale electricity generation located near customers, known as Distributed Generation (DG), is driven primarily by emerging technologies, environmental regulations and concerns, electricity market restructuring, and growing customer demand for increased quality and reliability of the electricity supply. Wind turbines are one of the renewable DG technologies that have become an important source of electricity in many parts of the world. Wind power can be used in many places to provide a viable solution to rising demand, energy security and independence, and climate change mitigation. This research aims broadly at facilitating the integration of wind-based DG without jeopardizing the system’s economics and reliability. To achieve this goal, the thesis tackles wind power from three perspectives: those of the policy maker, the investor, and the system operator. Generally, the economic viability of a project is determined within the framework of relevant policies. Therefore, these policies influence the decisions of potential investors in wind power. From this perspective, chapters 3 and 4 investigate the influence of policies on the economic viability of wind-based DG projects. In chapter 3, the role of Ontario’s taxation and incentive policies in the economic viability of wind-based DG projects is investigated. In this study, the effects of provincial income taxes, capital cost allowances, property taxes, and relevant federal incentives are considered. Net Present Value (NPV) and Internal Rate of Return (IRR) for different scenarios are used to assess the project’s viability under the Ontario Standard Offer Program (SOP) for wind power. In chapter 4, the thesis proposes the use of wind power as a source of electricity in a new city being developed in the Duqm area of Oman, where no policies supporting renewable energy exist. The study shows that the cost of electricity produced by wind turbines is higher than that of the existing generation system, due to the subsidized prices of domestically available natural gas. However, given high international natural gas prices, the country’s long-term Liquefied Natural Gas (LNG) export obligations, and the expansion of natural gas-based industries, investments in wind power in Duqm can be justified. A feed-in tariff and capital cost allowance policies are recommended to facilitate investments in this sector. From a wind-based DG investor’s perspective, the optimal selection of wind turbines can make wind power more economical, as illustrated in chapters 5 and 6. In chapter 5, the thesis presents a new generic model for Capacity Factor (CF) estimation using wind speed characteristics at any site and the power performance curve parameters of any pitch-regulated wind turbine. Compared to the existing model, the proposed formulation is simpler and results in more accurate CF estimation. CF models can be used by wind-based DG investors for optimal turbine-site matching applications. However, in chapter 6, the thesis demonstrates that using CF models as the sole basis for turbine-site matching applications tends to produce results that are biased towards higher towers but do not include the associated costs. Therefore, a novel formulation for the turbine-site matching problem, based on a modified CF formulation that does include turbine tower height, is introduced in chapter 6. The proposed universal Turbine-Site Matching Index (TSMI) also includes the effects of turbine rated power and tower height on the initial capital cost of wind turbines. Chapter 7 tackles wind power from a power system operator’s perspective. Despite wind power benefits, the effects of its intermittent nature on power systems need to be carefully examined as penetration levels increase. In this chapter, the thesis investigates the effects of different temporal wind profiles on the scheduling costs of thermal generation units. Two profiles are considered: synoptic-dominated and diurnal-dominated variations of aggregated wind power. To simulate wind profile impacts, a linear mixed-integer unit commitment problem is formulated in a GAMS environment. The uncertainty associated with wind power is represented using a chance constrained formulation. The simulation results illustrate the significant impacts of different wind profiles on fuel saving benefits, startup costs, and wind power curtailments. In addition, the results demonstrate the importance of the wide geographical dispersion of wind power production facilities to minimize the impacts of network constraints on the value of the harvested wind energy and the amount of curtailed energy.
578

Development of Intelligent-Based Solar and Diesel-Wind Hybrid Power Control Systems

Chang-Chien, Nan-Yi 21 June 2010 (has links)
A solar and diesel-wind hybrid power control systems is proposed in the thesis. The system consists of solar power, wind power, diesel-engine, a static synchronous compensator and an intelligent power controller. MATLAB/Simulink was used to build the dynamic model and simulate the solar and diesel-wind hybrid power system. A static synchronous compensator was used to supply reactive power and regulate the voltage of the hybrid system. To achieve a fast and stable response for the real power control, an intelligent controller was proposed, which consists of the Radial Basis Function Network (RBFN) and the Elman Neural Network (ENN) for maximum power point tracking (MPPT). The pitch angle control of wind power uses ENN controller, and the output is fed to the wind turbine to achieve the MPPT. The solar system uses RBFN, and the output signal is used to control the DC / DC boost converters to achieve the MPPT.
579

Piezoelectric energy harvesting: vortex induced vibrations in plants, soap films, and arrays of cylinders

Hobbs, William Bradford 08 April 2010 (has links)
The goal of this project was to develop a wind generator that utilizes the collective oscillating motion of multiple piezoelectric devices. These devices would be an alternative to rotating turbine designs for low power generation, for use in applications such as remote power generation. A series of inexpensive devices were developed that harvested energy from vortex shedding, both as independent and cooperative devices. The behavior of single devices was studied, but more interestingly, the way that multiple devices arranged together can increase power output was studied. It was shown that individual devices could harvest more energy if they were placed as specific positions relative to the vortices shed by devices upstream. Through investigating the behavior of these devices, fundamental principles of the phenomenon of vortex induced vibrations were explored. Methods were developed to measure the amplitude and frequency of these vibrations in a wind tunnel, through high speed video and correlations that were found between oscillation and power output from the piezoelectric transducers. Similarly, vortex induced vibrations were explored in an approximation of a two dimensional system in a flowing soap film.
580

Windmill driven water pump for small-scale irrigation and domestic use : In Lake Victoria basin

Salomonsson, Sara, Thoresson, Helena January 2010 (has links)
<p>This project is a combination of mechanical engineering and sustainable development in developing countries. The goal has been to build a windmill driven water pump and to design a small-scale irrigation system for SCC-Vi Agroforestry’s demonstration farm in Musoma, Mara region, Tanzania. The purpose was to enable SCC-Vi Agroforestry to demonstrate and spread knowledge about these techniques to farmers in the region.</p><p>In 2007, two students from Halmstad University conducted a field study in the Mara region and found that many farmers lack clean and running water. Back in Sweden they constructed a prototype of a windmill that employs wind energy to pump water using a semi-rotary pump. The intention is that local farmers should be able to build their own windmill, and thus have running water in their household. However, the windmill has never been built in Tanzania.</p><p>The windmill construction in this report is based on the prototype, but the original drawings were changed to fit the specific situation in Tanzania better. Important throughout the project has been to minimise cost and to only use material that local farmers can get hold of. Building and assembling of the windmill were then performed by the authors in co-operation with local workers. The windmill drives a pump that pumps water from a well to a tank for further use in irrigation.</p><p>Calculations have been made on the energy available in the wind and an energy analysis was then performed to see what wind speed is required for the system to work. If wind speed is low, the windmill can be adjusted by placing the connecting rod closer to the rotation centre where it requires less work to function. As a result of that, the volume of water per stroke will decrease and it will take longer time to fill the tank. This project was carried out during the rainy season when there is less wind; therefore the windmill has not been tested during optimal wind speed conditions. The tests that have been performed during the circumstances at the time showed that the performance of the windmill is consistent with the theoretical calculations.</p><p>A proposed design for a simple drip irrigation system has been developed based on the conditions at the project area. It is constructed of plastic pipes with holes that emit water. Covers are in place to prevent soil from clogging the holes. Building the irrigation system was not part of this project.</p>

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