Com o déficit de energia que atualmente preocupa o setor elétrico brasileiro, ameaçando os consumidores com a possibilidade de novos racionamentos, surge a perspectiva de aumento de produção de energia, através da criação de usinas eólicas para suprir essa demanda. Entretanto, esta forma de geração, sabidamente, provoca distorções na qualidade de energia fornecida, principalmente quanto à geração de harmônicas, que acabam por interferir diretamente nas cargas podendo provocar danos a equipamentos e instalações. Por esse motivo, este trabalho visa analisar a contribuição desse tipo de geração no sistema elétrico e discutir, com base em estudos experimentais realizados em modelos de aerogeradores e diretamente em unidades geradoras instaladas em plantas de geração eólica, as perturbações harmônicas geradas pelo controle de tensão e frequência do sistema. A metodologia utilizada será a de medição das distorções harmônicas, através de analisadores de qualidade de energia, instalados primeiramente em modelos laboratoriais dos principais tipos de aerogeradores existentes no mercado, medindo as perturbações em diversas situações de carga, obedecendo ao estabelecido na norma NBR-IEC- 61400-21/2010 Medição e Avaliação da Qualidade de Energia de Aerogeradores Conectados a Rede. / With the energy deficit that currently worries the Brazilian electric sector, threatening consumers with the possibility of further rationing comes the prospect of increased energy production through the creation of wind farms to meet this demand. However, this form of generation is known to distort the quality of power supplied, especially as the generation of harmonics, which ultimately interfere directly in the loads can cause damage to equipment and facilities. Therefore, this study aims to analyze the contribution of this type of generation on the electrical system and discuss, based on experimental studies in directly generating units installed in wind generation plants, disturbances generated by harmonic voltage and frequency control system. The methodology will be the measurement of harmonic distortion through power quality analyzers, installed primarily in laboratory models of the main types of wind turbines on the market, measuring disturbances in various loading conditions, obeying the established standard NBR-IEC-61400-21/2010 - Measurement and Evaluation of Power Quality of Wind Turbines Connected Network.

Access to reliable electric power is considered by the developed world to be a minimum requirement for a reasonable standard of living. In addition to meeting a fluctuating demand, the modern electricity industry must now integrate intermittent generation sources like wind into the grid. Reserve margin allocation (RMA) for an acceptable loss of load expectation (LOLE) allows traditional generators to maintain grid reliability in the presence of small penetrations of wind energy. However, traditional RMA over-allocates the reserve capacity in the presence of short-term intermittency mitigation techniques like energy storage and demand response. For economic operation of the modern, grid better characterization techniques are needed for reserve margin reduction behavior in the presence of wind energy. This thesis addresses this challenge with a quantitative RMA analysis using real-world and simulated wind data for three different grid scenarios, with and without intermittency mitigation. The research is novel in its first-principles approach and its investigation into the practical validity of the analogy between demand response and energy response.

Distributed generation has the potential to reduce the supply-demand gap emerging in New Zealand’s electricity market. Thereby it can improve the overall network efficiency, harness renewable energy resources and reduce the need for upgrading of existing distribution lines. A typical New Zealand rural community consisting of three adjacent farms at Totara Valley near Woodville represents a demonstration site on distributed generation for Massey University and Industrial Research Limited. Local renewable energy resources are being used for the purpose of sustainable development. Alternative micro-scale technologies are being combined to achieve a valuable network support. This paper is an in-depth report on the implementation process of the HyLink system; a system which utilises hydrogen as an energy carrier to balance and transport the fluctuating wind power. The report documents its development from the laboratory stage to commissioning at Totara Valley, which was carried out under direction of Industrial Research Limited. The PEM electrolyser’s performance at different stack temperatures was investigated. It was found that hydrogen production increases at the same voltage with a higher stack temperature. This is due to the improved kinetics of the electrochemical reactions and decreased thermodynamic energy requirement for water electrolysis. The electrolyser efficiency measurement at the half of its maximal power input (247 W) resulted in 65.3%. Thereby the stack temperature attained less than half of the allowed limit of 80°C. The capture of the excess heat by insulation can improve the electrolyser’s efficiency. Pressure tests were performed on the 2 km long pipeline at Totara Valley using hydrogen and natural gas in order to test their permeability. The results were compared with previous studies at Massey University and with data obtained from the industry. The hydrogen permeability was measured to be 5.5 * 10[to the power of]-16 mol m m[to the power of]-2 s[to the power of]-1 Pa[to the power of]-1 for a 2 km MDPE pipe. This is about half the result obtained from previous studies on hydrogen permeability through MDPE at Massey University which was undertaken at room temperature. The reason for this discrepancy is likely to be the lower ambient temperature during the measurement at Totara Valley, which can be supported with the Arrhenius equation. It was furthermore measured that the power loss due to hydrogen diffusion through the pipeline walls during the fuel cell operation is about 1.5 W at the current system operation mode. A techno-economic analysis of the system was undertaken applying the micro-power optimisation software HOMER as a simulation tool. Two operation modes of the system were investigated, the load following and the peak demand compensating. The simulation results reveal that the durability and the cost of the electrochemical energy conversion devices; electrolyser and fuel cell, are the main hurdles which need to be overcome on the path in introducing hydrogen based energy systems like HyLink. Finally, economic optimisation modelling of the small-scale system by best component alignment was performed. It was found that the electrolyser capacity down-rating of 80% in relation to the wind turbine capacity, leads to a minimal system levelised cost. In addition to this, the impact of various wind turbine/electrolyser subsystems and pipeline storage capacities on the fuel cell capacity factor and on the system levelised cost in the load following operation mode was analysed. The outcomes can be useful for further HyLink related energy system planning.

Distributed generation has the potential to reduce the supply-demand gap emerging in New Zealand’s electricity market. Thereby it can improve the overall network efficiency, harness renewable energy resources and reduce the need for upgrading of existing distribution lines. A typical New Zealand rural community consisting of three adjacent farms at Totara Valley near Woodville represents a demonstration site on distributed generation for Massey University and Industrial Research Limited. Local renewable energy resources are being used for the purpose of sustainable development. Alternative micro-scale technologies are being combined to achieve a valuable network support. This paper is an in-depth report on the implementation process of the HyLink system; a system which utilises hydrogen as an energy carrier to balance and transport the fluctuating wind power. The report documents its development from the laboratory stage to commissioning at Totara Valley, which was carried out under direction of Industrial Research Limited. The PEM electrolyser’s performance at different stack temperatures was investigated. It was found that hydrogen production increases at the same voltage with a higher stack temperature. This is due to the improved kinetics of the electrochemical reactions and decreased thermodynamic energy requirement for water electrolysis. The electrolyser efficiency measurement at the half of its maximal power input (247 W) resulted in 65.3%. Thereby the stack temperature attained less than half of the allowed limit of 80°C. The capture of the excess heat by insulation can improve the electrolyser’s efficiency. Pressure tests were performed on the 2 km long pipeline at Totara Valley using hydrogen and natural gas in order to test their permeability. The results were compared with previous studies at Massey University and with data obtained from the industry. The hydrogen permeability was measured to be 5.5 * 10[to the power of]-16 mol m m[to the power of]-2 s[to the power of]-1 Pa[to the power of]-1 for a 2 km MDPE pipe. This is about half the result obtained from previous studies on hydrogen permeability through MDPE at Massey University which was undertaken at room temperature. The reason for this discrepancy is likely to be the lower ambient temperature during the measurement at Totara Valley, which can be supported with the Arrhenius equation. It was furthermore measured that the power loss due to hydrogen diffusion through the pipeline walls during the fuel cell operation is about 1.5 W at the current system operation mode. A techno-economic analysis of the system was undertaken applying the micro-power optimisation software HOMER as a simulation tool. Two operation modes of the system were investigated, the load following and the peak demand compensating. The simulation results reveal that the durability and the cost of the electrochemical energy conversion devices; electrolyser and fuel cell, are the main hurdles which need to be overcome on the path in introducing hydrogen based energy systems like HyLink. Finally, economic optimisation modelling of the small-scale system by best component alignment was performed. It was found that the electrolyser capacity down-rating of 80% in relation to the wind turbine capacity, leads to a minimal system levelised cost. In addition to this, the impact of various wind turbine/electrolyser subsystems and pipeline storage capacities on the fuel cell capacity factor and on the system levelised cost in the load following operation mode was analysed. The outcomes can be useful for further HyLink related energy system planning.

Distributed generation has the potential to reduce the supply-demand gap emerging in New Zealand’s electricity market. Thereby it can improve the overall network efficiency, harness renewable energy resources and reduce the need for upgrading of existing distribution lines. A typical New Zealand rural community consisting of three adjacent farms at Totara Valley near Woodville represents a demonstration site on distributed generation for Massey University and Industrial Research Limited. Local renewable energy resources are being used for the purpose of sustainable development. Alternative micro-scale technologies are being combined to achieve a valuable network support. This paper is an in-depth report on the implementation process of the HyLink system; a system which utilises hydrogen as an energy carrier to balance and transport the fluctuating wind power. The report documents its development from the laboratory stage to commissioning at Totara Valley, which was carried out under direction of Industrial Research Limited. The PEM electrolyser’s performance at different stack temperatures was investigated. It was found that hydrogen production increases at the same voltage with a higher stack temperature. This is due to the improved kinetics of the electrochemical reactions and decreased thermodynamic energy requirement for water electrolysis. The electrolyser efficiency measurement at the half of its maximal power input (247 W) resulted in 65.3%. Thereby the stack temperature attained less than half of the allowed limit of 80°C. The capture of the excess heat by insulation can improve the electrolyser’s efficiency. Pressure tests were performed on the 2 km long pipeline at Totara Valley using hydrogen and natural gas in order to test their permeability. The results were compared with previous studies at Massey University and with data obtained from the industry. The hydrogen permeability was measured to be 5.5 * 10[to the power of]-16 mol m m[to the power of]-2 s[to the power of]-1 Pa[to the power of]-1 for a 2 km MDPE pipe. This is about half the result obtained from previous studies on hydrogen permeability through MDPE at Massey University which was undertaken at room temperature. The reason for this discrepancy is likely to be the lower ambient temperature during the measurement at Totara Valley, which can be supported with the Arrhenius equation. It was furthermore measured that the power loss due to hydrogen diffusion through the pipeline walls during the fuel cell operation is about 1.5 W at the current system operation mode. A techno-economic analysis of the system was undertaken applying the micro-power optimisation software HOMER as a simulation tool. Two operation modes of the system were investigated, the load following and the peak demand compensating. The simulation results reveal that the durability and the cost of the electrochemical energy conversion devices; electrolyser and fuel cell, are the main hurdles which need to be overcome on the path in introducing hydrogen based energy systems like HyLink. Finally, economic optimisation modelling of the small-scale system by best component alignment was performed. It was found that the electrolyser capacity down-rating of 80% in relation to the wind turbine capacity, leads to a minimal system levelised cost. In addition to this, the impact of various wind turbine/electrolyser subsystems and pipeline storage capacities on the fuel cell capacity factor and on the system levelised cost in the load following operation mode was analysed. The outcomes can be useful for further HyLink related energy system planning.

<p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p> / <p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p>

Wind energy is a promising alternative energy source due to its environmental, economic, and social benefits and, as such, has garnered public support and government incentives for its development and implementation. With the growing number of wind parks in Oregon, a life cycle assessment (LCA) study for a representative new wind park is needed to investigate the potential impacts on the environment. One of the major drawbacks of wind energy generation is its variability due to the stochastic nature of wind. To make wind energy a more reliable source, wind energy generation should be supplemented with controllable energy generation or storage. Thus, the aim of this research is to improve the understanding of the effects of supplemental energy systems on the environmental impacts of wind energy systems. First, the environmental impact of a single wind turbine is examined from raw material extraction to the end of life stage. Research needs are identified to support the assessment of the environmental impacts of wind energy and supplemental energy systems from a life cycle perspective. Next, supplemental electricity generation systems investigated are biomass, hydro, and natural gas electricity generation, and zinc-bromine battery storage. Finally, the results for each system are compared to coal energy generation. It appears that the wind park has lower environmental impact than coal energy generation when paired with any of the complimentary systems investigated. Overall, hydropower appears to be the best option to supplement wind power from an environmental perspective for a potential wind park site in northern Oregon. / Graduation date: 2013

No description available.

Wind power is a renewable energy source that is increasingly used all over the world. Most wind turbines have a horizontal axis of rotation but a few have a vertical axis of rotation. The concept presented in this thesis is a straight-bladed vertical axis wind turbine with a direct driven cable-wound permanent magnet synchronous generator. A comparison of the two different types of wind turbines, vertical axis wind turbines and horizontal axis wind turbines, have been performed considering several different aspects. However, the main focus in this thesis is on the generator. Several generators have been modelled with a combined field and circuit model, which has been solved by using the finite element method. A 12 kW generator has been designed, which has a high overall efficiency and a high overload capability. The generator has been constructed at the department and was tested in the laboratory before being mounted in a vertical axis wind turbine. Results from experiments correspond well with results from simulations. The generator has been tested for different loading conditions and the harmonic content of the voltage has been analysed. A 12 kW vertical axis wind turbine was completed and tests have been performed. The results are encouraging and further studies on the prototype will be performed in the future. The simulation method has been used to study electromagnetic losses in several generators. The comparison showed that the average losses should be considered when a variable speed generator for wind power is designed and it concluded that the design optimization process becomes a compromise between lowering the electromagnetic losses and having high overload capability. When constructing a wind turbine, it is important to consider vibrations in the structure. Torsional vibrations in the drive shaft connecting the turbine to the rotor of the generator have been studied. It is shown that a direct driven generator is to prefer over an induction generator with a gearbox when torsional vibrations are concerned. This thesis is based on eight papers all concerning vertical axis wind turbines with three of them focusing on the generator.

Worldwide interest in renewable energy systems has increased dramatically, due to environmental concerns like climate change and other factors. Wind power is a major source of sustainable energy, and can be harvested using both horizontal and vertical axis wind turbines. This thesis presents studies of a vertical axis wind turbine performance for applications in urban areas. Numerical simulations with FLUENT software are presented to predict the fluid flow through a novel Zephyr vertical axis wind turbine(VAWT). Simulations of air flow through the turbine rotor were performed to analyze the performance characteristics of the device. Major blade geometries were examined. A multiple reference frame (MRF) model capability of FLUENT was used to express the dimensionless form of power output of the wind turbine as a function of the wind freestream velocity and the rotor's rotational speed. The simulation results exhibit close agreement with a stream-tube momentum model. / UOIT