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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.
31

[en] MODEL FOR SELECTING SITES FOR PUMPED STORAGE IMPLEMENTATION: AN APPROACH BASED ON GEOGRAPHIC INFORMATION SYSTEM / [pt] MODELO PARA SELEÇÃO DE LOCAIS PARA A IMPLANTAÇÃO DE USINAS HIDRELÉTRICAS REVERSÍVEIS: UMA ABORDAGEM BASEADA EM SISTEMA DE INFORMAÇÃO GEOGRÁFICA

LUIZ RODOLPHO SAURET CAVALCANTI DE ALBUQUERQUE 23 June 2022 (has links)
[pt] A recente expansão das fontes renováveis para geração de energia elétrica decorre do encarecimento dos combustíveis fósseis e da preocupação com impactos ambientais e mudanças climáticas, assim como de avanços tecnológicos e da queda de seus custos de implantação. Entretanto, a natureza intermitente e sazonal dos recursos naturais, como vento e irradiação solar, pode afetar a operação do sistema elétrico. Uma alternativa para dar equilíbrio à carga do sistema, proporcionando ainda outros benefícios, é o armazenamento de energia. Uma tecnologia de larga escala para armazenamento é a de bombeamento hidráulico por meio de usinas hidrelétricas reversíveis (UHR), que oferecem mais eficiência, tempo de resposta mais rápido e vida útil mais longa que outras alternativas. Tendo em vista as lacunas teóricas no campo acadêmico, a dissertação propõe um modelo para identificação de locais potenciais para implantação dessas usinas, com o auxílio de ferramentas de sistema de informação geográfica e de formulações matemáticas que consideram critérios fisiográficos, energéticos, econômicos e socioambientais. Partindo de uma abordagem baseada no conceito de geomorphons combinada com soluções de um problema de otimização, o modelo proposto tem por objetivo definir uma formulação que busque minimizar os custos de construção de uma UHR. A demonstração da aplicabilidade do modelo é feita em torno do reservatório da UHE Sobradinho, e os resultados são discutidos a partir da comparação dos locais selecionados e dos custos obtidos. Pode-se concluir que é possível identificar potenciais locais para implantação de UHR a partir desse modelo, o que pode beneficiar agentes de planejamento do setor elétrico, bem como empresas que estejam interessadas em investir nesta tecnologia. / [en] The expansion of the use of renewable sources for electricity generation in recent years is a result of the increase of fossil fuels costs and the growing concern with climate change and the impacts on the environment, as well as technological advances and the reduction in their implementation costs. However, the availability of some natural resources for renewable energy matrices, such as wind and solar irradiation, has an intermittent and seasonal nature, which may affect the electrical system operation (CANALES et al., 2015; KELMAN & HARRISON, 2019). One of the alternatives to balance the system load is energy storage, which offers benefits to the electricity provision (ancillary services, for example) and regulates the frequency in times of high demand with low energy supply from renewables, contributing with the necessary inertia so that demand does not change instantly (BARBOUR et al., 2016). The most widely large-scale technology used for storage in the world is hydraulic pumping through pumped storage hydropower – PSH (GUITTET et al., 2016; IHA, 2018). Compared to other technologies, it provides a solution with high efficiency, faster response time and longer useful life (REHMAN et al., 2015). The operation of the plants is characterized by the pumping of water from a lower reservoir for its accumulation in an upper reservoir for energy generation in periods of high demand (BARBOUR et al., 2016). Energy storage alternatives are already on the agenda in the Brazilian energy sector as an option to ensure the system development in an economic and sustainable manner. In the 2030 Ten-Year Energy Expansion Plan (EPE, 2021b), PSH is highlighted as one of the resources to expand the offer for rush hour demand response. EPE understands that preliminary studies are an important step to support the sector s planning and guide the definition of regulatory aspects, which do not yet exist, related to the systemic benefits of this type of solution.
32

Ökad lokal nytta av förnyelsebar energiproduktion med hybridkraftverk

Beijner, David January 2018 (has links)
Förnyelsebar och miljövänlig elproduktion är en förutsättning för det mer eller mindre miljömässigt positiva värdet hos de produkter och processer som förbrukar elenergi. Det räcker inte med att dessa produkter och processer är effektiva i sitt användande av el om denna el är producerad med icke förnyelsebara metoder. Målet simuleringsprogram som kan simulera ett hybridkraftverk som använder sig av vindkraft och vattenkraft. Resultatet av detta projekt är ett simuleringsprogram som kan uppskatta storleken på ett pumpkraftverk i form av hur många megawatt dess vattenturbin behöver vara samt hur stor reservoar som behövs. Dessutom uppskattas hur många vindkraftverk som krävs i kombination med vattenkraftverket för att nå en önskad minskning av elektricitet från icke förnyelsebara källor.  med detta projekt är skapandet av ett / Renewable and environmentally friendly electricity production is a necessity for the relative positive value of the products and processes that consumes electricity. It is not enough that these products and processes in and of themselves are effective in their use of electricity if that electricity is produced with non- renewable means. The goal of this project is the creation of a simulation software that can simulate a hybrid powerplant composed of wind turbines and a hydro powerplant. The result of this project is a simulation software that is able is to approximate the size of a pumped-storage megawatts and the size of the reservoir needed. In addition, the software calculates the amount of wind turbines needed in combination with the hydro powerplant to achieve a desired decrease in non-renewable electricity.
33

[en] PROPOSAL OF PUBLIC POLICIES FOR INSERTING PUMPED STORAGE HYDROELECTRIC PLANTS IN BRAZIL: A MULTICRITERIA APPROACH / [pt] PROPOSIÇÃO DE POLÍTICAS PÚBLICAS PARA INSERÇÃO DE USINAS HIDRELÉTRICAS REVERSÍVEIS NO BRASIL: UMA ABORDAGEM MULTICRITÉRIO

GUILHERME VIEIRA COSENTINO 21 November 2022 (has links)
[pt] A inserção de sistemas de armazenamento de energia é uma tendência global observada no cenário de diversificação energética de vários países no mundo. Considerando a predominância da geração hídrica centralizada na matriz elétrica brasileira, as Usinas Hidrelétricas Reversíveis possuem uma tendência à utilização dentro do Sistema Interligado Nacional (SIN). Entretanto, tal processo de inserção deve considerar as possíveis alterações no marco regulatório advindas de novas políticas regulatórias para o setor elétrico brasileiro. A seleção destas políticas deve considerar diversos critérios e várias dimensões. Além disso, a política escolhida deve considerar uma Análise de Impacto Regulatório para sua efetividade. O objetivo principal desta dissertação é propor um modelo de seleção e avaliação dessas políticas, utilizando um processo de análise de impacto regulatório (AIR), com o auxílio de métodos multicritério de apoio à decisão (MCDM). O modelo definido foi proposto em seis etapas: definição do problema regulatório; determinação do framework regulatório; mapeamento das alternativas de ação; análise benefício-custo conduzida com o método AHP; seleção da política preferida com o método fuzzy-TOPSIS e monitoramento e avaliação desta política. A modelagem foi aplicada para as seguintes cinco políticas definidas: criação de um mercado de capacidade; criação de um mercado de flexibilidade; implementação de um leilão multiatributos; implementação de um leilão de capacidade; e adoção de uma política de incentivos. Os resultados foram comparados com algumas referências, confirmando a aplicabilidade da metodologia e indicando que o desenvolvimento do modelo proposto preencheu lacunas na literatura referente às aplicações de abordagem multicritério para políticas energéticas. / [en] The insertion of the energy storage systems is a global trend observed in the energy diversification scenario of several countries in the world. Considering the predominance of centralized hydroelectric generation in the brazilian electric matrix, Pumped Storage Hydroelectric Plans tend to be used within the National Interconnected System (SIN). However, such insertion process must consider the new changes in the regulatory framework arising from Brazilian regulatory policies for the sector. The selection of these policies must consider several and several dimensions. In addition, the chosen policy must consider a Regulatory Impact Analysis for its own. The main objective of this dissertation is to propose a model for the selection and evaluation of these policies, using a Regulatory Impact Analysis (RIA) process, with the aid of multicriteria decision making methods (MCDM). The defined model was proposed in six stages: definition of the regulatory problem; determination of the regulatory framework; mapping of action alternatives; benefit-cost analysis with the AHP method; selection of preferred policy with the fuzzyTOPSIS method and monitoring and evaluation of this policy. The modeling was applied to the following five policies: creating a capacity market; creation of a flexibility market; implementation of a multi-attribute auction; implementation of a capacity auction; and adoption of an incentive policy. The policies were compared with some references, confirming the applicability of the methodology and indicating the development of the proposed model, gaps in the literature regarding the applications of multicriteria for energy.
34

Management of Artificial Recharge Wells for Groundwater Quality Control

Wilson, L. G. 23 April 1971 (has links)
From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / Recharge wells may be used in various problems relating to chemical water quality because of the phenomenon of in-aquifer mixing. This paper reviews specific recharge well-mixing techniques of possible utility in underground mixing operations for nitrate control. Illustrative data from field studies at a recharge site near Tucson, Arizona are presented. Both single- and 2-well types of mixing were investigated. In single-well operations, effluent recharge and pumping of the subsequent mixture occur at the same well. Differences in chlorine ion levels were used to distinguish between recharge effluent and native groundwater. Undiluted effluent was discharged in single-well operations until a pumped volume ratio of about 0.4 was attained. Dilution increased steadily with increased pumping and the relative concentration versus pumped volume curve was s-shaped. Seven-day pauses after effluent recharge resulted in immediate pumping of almost completely diluted water, probably because groundwater movement swept the effluent beyond the pumping unit during the pause. With 2-well pumping, the chlorine breakthrough curve reached a constant level at about 13 days and was close to that of the pause-type, single-well regime.
35

The Compartmented Reservoir: Efficient Water Storage in Flat Terrain Areas of Arizona

Cluff, C. B. 15 April 1978 (has links)
From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / The compartmented reservoir is presented as an efficient method of storing water in areas of Arizona having a relatively flat terrain where there is a significant water loss through evaporation. The flat terrain makes it difficult to avoid large surface- area-to-water-volume ratios when using a conventional reservoir. Large water losses through evaporation can be reduced by compartmentalizing shallow impervious reservoirs and in flat terrain concentrating water by pumping it from one compartment to another. Concentrating the water reduces the surface-area-to-water-volume ratio to a minimum, thus decreasing evaporation losses by reducing both the temperature and exposure of the water to the atmosphere. Portable, high-capacity pumps make the method economical for small reservoirs as well as for relatively large reservoirs. Further, the amount of water available for beneficial consumption is usually more than the amount of water pumped for concentration. A Compartmented Reservoir Optimization Program (CROP-76) has been developed for selecting the optimal design configuration. The program has been utilized in designing several systems including several in Arizona. Through the use of the model, the interrelationship of the parameters have been determined. These parameters are volume, area, depth, and slope of the embankment around each compartment. These parameters interface with the parameters describing rainfall and hydrologic characteristics of the watershed. The water -yield model used in CROP-76 requires inputs of watershed area, daily precipitation and daily and maximum depletion. In addition, three sets of seasonal modifying coefficients are required either through calibration or estimated by an experienced hydrologist. The model can determine runoff from two types of watersheds, a natural and /or treated catchment. Additional inputs of CROP-76 are the surface water evaporation rate and the amount and type of consumptive use.
36

Posouzení výhodnosti výstavby přečerpávací vodní elektrárny velkého výkonu v lokalitě Cukrová bouda, okres Šumperk / The assessment of advantages of construction of large hydroelectric power plants in the area of Cukrova bouda, district Sumperk

Knápek, Michal January 2012 (has links)
The subject matter of the master´s thesis is, in particular, an evaluation of the advantageousness of the construction of a pumped-storage hydroelectric power station in the vicinity of Cukrová Bouda. In the master´s thesis introduction the utilisation of pumped-storage hydroelectric power stations in providing reserve power generation to the operator of a power transmission system is discussed. The thesis then focuses on a technical design solution where two alternatives are drawn up for which the nominal parameters of individual designs for a pumped-storage hydroelectric power station are specified. The following part deals with the impact of the structure and the plant’s subsequent operation on the environment. A further key part is the determination of investment and subsequent operating costs and an evaluation of the plant according to economic pointers. The final part of the master´s thesis contains a SWOT analysis and an assumed programme of works for the plant’s preparation and actual construction. The conclusion contains an overall evaluation.

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