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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.
101

[en] OPTIMIZATION OF HYDROELECTRIC INVENTORY STUDIES / [pt] OTIMIZAÇÃO DE ESTUDOS DE INVENTÁRIO HIDROELÉTRICOS

LARISSA FIGUEIREDO TERRA DE FARIA 04 May 2011 (has links)
[pt] O desenvolvimento de estudos de inventário para Pequenas Centrais Hidroelétricas – PCHs – é uma atividade custosa e demorada. A motivação desta dissertação é, de forma rápida e econômica, verificar a real viabilidade destes projetos. Um modelo computacional foi criado para automatizar estudos de inventário, identificando o potencial de geração hidroelétrica e os locais de instalação dos projetos. A partir da identificação do potencial, é estudada a definição de possíveis eixos de barramento, ou seja, resolve-se o problema da divisão de quedas para um determinado rio. Este trabalho, então, discute a implementação de um modelo para avaliação do potencial hidroelétrico que seleciona e dimensiona projetos hidroelétricos em uma bacia hidrográfica. Este potencial é desenvolvido baseando-se na maximização do benefício líquido, e inclui restrições sócio-ambientais que podem ser adaptadas a diferentes regulamentos locais. Através desta automatização, espera-se reduzir os riscos de empresários investirem uma quantidade de dinheiro significativa em bacias hidrográficas pouco promissoras. / [en] The development of inventory studies for Small Hydropower Plants is a costly and time consuming activity. The motivation of this dissertation is to, quickly and economically, verify the true viability of these projects. A computational model was created to automate inventory studies, identifying the hydroelectric generation potential and the projects’ installation sites. After the identification of the potential, the definition of project siting and project sizing is studied. In other words, the model determines the most adequate sites to build dams among several candidate locations and, for each selected case, the plant design (gross head, installed capacity, reservoir size and others). This potential is developed through the maximization of total net benefit, and includes environmental constraints that can be adapted to different regulations. Through this automation, the risks for entrepreneurs investing a significant amount of money in unpromising river basins are expected to reduce.
102

Electric power system production costing and reliability analysis including hydroelectric, storage, and time dependent power plants

Finger, Susan 02 1900 (has links)
Prepared for the U.S. Dept. of Energy under Contract no. EX-76-A-01-2295, Task order 37.
103

Migration problems of Atlantic salmon (Salmo salar L.) in flow regulated rivers /

Rivinoja, Peter. January 2005 (has links)
Thesis (doctoral)--Swedish University of Agricultural Sciences, 2005. / Thesis documentation sheet inserted. Appendix includes six papers and manuscripts co-authored with others. Also issued electronically via World Wide Web in PDF format; online version lacks appendix of papers.
104

'Clean Energy' At What Cost?

Conrad, Rachel E 01 April 2013 (has links)
Ecuador was ‘refounded’ at the turn of the 21st century, with the articulation of progressive and inclusive ideals in a new Constitution. Social movements and leftist intellectuals in Ecuador have expressed that president Rafael Correa has failed to uphold the 2008 Constitution’s goals and values. President Correa and his Alianza PAIS government have utilized the rhetoric of the revolutionary ideals articulated in the Constitution, but in practice, they have continued to implement the status quo Western development model, and a large part of their development strategy involves ‘neo-extractive’ activities. Hydroelectric energy production is contributing to the ‘neo-extractive’ development model in Ecuador, and its implementation has often violated Constitutional rights. This thesis is an analysis of natural resource extraction in Ecuador and its social repercussions, with a focus on hydroelectric energy production. It is shown that the hydroelectric industry in Ecuador is not as “clean,” sustainable, or non-extractive as it is purported to be, through a case study of the San José del Tambo hydroelectric project and the exploration of an international support for hydroelectric extractivism, the United Nations Clean Development Mechanism, and its misleading framing of extractive projects as “sustainable development.” Social movements in Ecuador are acting to reverse the perversion of their originally revolutionary ideals, and to implement a post-extractive model informed by those revolutionary ideals.
105

Greenhouse gas cycling in experimental boreal reservoirs

Venkiteswaran, Jason James January 2008 (has links)
Hydroelectric reservoirs account for 59% of the installed electricity generating capacity in Canada and 26% in Ontario. Reservoirs also provide irrigation capacity, drinking water, and recreational opportunities. Further, they continue to be built in northern Canada, neighbouring boreal countries, and around the world. Yet given their socio-economic importance, they are understudied with respect to greenhouse gas emissions, nutrient and mercury cycling, and aquatic metabolism. As one of many electricity generating options, hydroelectricity is viewed as well-tested because of its long history and diverse applications in mega-projects, run-of-the-river dams, and small, local applications. It is also considered renewable from a fuel stand-point because an adequate long-term supply of water is assumed. One of several significant criticisms of hydroelectric development is that reservoirs may be a significant source of greenhouse gases to the atmosphere relative to the amount of electricity produced due to flooding the landscape. As a result of the dearth of information on reservoir development and both greenhouse gases and aquatic metabolism, a pair of whole-ecosystem reservoir experiments were conducted staring in 1991. Three upland boreal forest reservoirs with differing amounts of pre-flood stored organic carbon were built in northwestern Ontario and flooded for five years. The rates of net greenhouse gas production in these reservoirs were determined by calculating mass budgets for carbon dioxide and methane. Additionally, rates of biological processes were determined by combining the mass budgets with measurements of the stable isotopes of carbon and oxygen. Assembling mass and isotope-mass budgets required three related projects on gas exchange, methane oxidation, and oxygen isotopes. To estimate the gas exchange coefficient for each of the upland reservoirs, a comparative-methods study was undertaken. Methane oxidation enrichment factors were determined in upland and wetland boreal reservoirs so that the importance of methane oxidation in these ecosystems could be assessed. In order to interpret the diel changes in both oxygen concentrations and their isotopic ratios, a dynamic model was developed. This model, PoRGy, was successfully applied to the upland boreal reservoirs as well as prairie rivers and ponds. Further, PoRGy was used to understand the interplay between the key parameters that control oxygen concentrations, to compare aquatic ecosystems, to make quantitative estimates of ecosystem metabolism, and to assess the vulnerability of aquatic ecosystems under various environmental stressors. Carbon isotope-mass budgets were used to conclude that community respiration rates declined quickly in the upland reservoirs and had declined by half over five years. This suggested that the most labile organic carbon is quickly consumed but decomposition continued for the five-year life of the project. Net primary production rates were similar for three years, with a small peak in the second or third year, before declining by half by the fifth year. Together, these results indicated that aquatic metabolism slowed over five years while the reservoirs remained a source of greenhouse gases to the atmosphere each year. Net methane production was greatest in the third year of flooding then decreasing by about half by the fifth year. Methane ebullition also peaked in the third year and declined by two-thirds by the fifth year. Together, these results indicated that methanogenesis was greatest in the third year of flooding. The flux of methane to the atmosphere grew in importance relative to that of carbon dioxide over the five years of the experiment. Community respiration and primary production could not be estimated directly from the oxygen isotope-mass budgets since the oxygen respiration enrichment factor remains poorly constrained. Instead, three estimates were made, each based on a different assumption. In general, these estimates suggested that rates of community respiration and primary production decreased slightly for three years and most rapidly in the final two years. The oxygen isotope-mass budgets provided a new method for assessing and constraining community metabolism and greenhouse gas fluxes to the atmosphere. One of the major hypotheses of the whole-ecosystem reservoir experiments was that pre-flood organic carbon stores less tree boles were positively related to greenhouse gas fluxes. Within the three upland boreal forest reservoirs, this hypothesis did not hold true. Over five years, community respiration in the three reservoirs was within 5% of each other. When methane is included, to assess total greenhouse gas fluxes to the atmosphere, the reservoirs were within 1% of each other. Organic carbon stores were therefore poor short-term predictors of carbon lability and greenhouse gas fluxes. This research presented two methods for determining biological rates at the whole-ecosystem scale: one using carbon isotopes and one using oxygen isotopes. Temporal evolution of greenhouse gas cycling within the upland reservoirs was different than in the wetland reservoir and should inform how reservoir development is done vis-à-vis the amount of flooded land of each type versus electricity production. Medium-term estimates of greenhouse gas fluxes suggest that upland reservoirs do not have adequate pre-flood organic carbon stores to sustain elevated levels of decomposition the way wetlands do. The strong evidence of continued production of dissolved organic carbon in the upland reservoirs should concern operators of municipal drinking water reservoirs since elevated dissolved organic carbon can make disinfection difficult.
106

Greenhouse gas cycling in experimental boreal reservoirs

Venkiteswaran, Jason James January 2008 (has links)
Hydroelectric reservoirs account for 59% of the installed electricity generating capacity in Canada and 26% in Ontario. Reservoirs also provide irrigation capacity, drinking water, and recreational opportunities. Further, they continue to be built in northern Canada, neighbouring boreal countries, and around the world. Yet given their socio-economic importance, they are understudied with respect to greenhouse gas emissions, nutrient and mercury cycling, and aquatic metabolism. As one of many electricity generating options, hydroelectricity is viewed as well-tested because of its long history and diverse applications in mega-projects, run-of-the-river dams, and small, local applications. It is also considered renewable from a fuel stand-point because an adequate long-term supply of water is assumed. One of several significant criticisms of hydroelectric development is that reservoirs may be a significant source of greenhouse gases to the atmosphere relative to the amount of electricity produced due to flooding the landscape. As a result of the dearth of information on reservoir development and both greenhouse gases and aquatic metabolism, a pair of whole-ecosystem reservoir experiments were conducted staring in 1991. Three upland boreal forest reservoirs with differing amounts of pre-flood stored organic carbon were built in northwestern Ontario and flooded for five years. The rates of net greenhouse gas production in these reservoirs were determined by calculating mass budgets for carbon dioxide and methane. Additionally, rates of biological processes were determined by combining the mass budgets with measurements of the stable isotopes of carbon and oxygen. Assembling mass and isotope-mass budgets required three related projects on gas exchange, methane oxidation, and oxygen isotopes. To estimate the gas exchange coefficient for each of the upland reservoirs, a comparative-methods study was undertaken. Methane oxidation enrichment factors were determined in upland and wetland boreal reservoirs so that the importance of methane oxidation in these ecosystems could be assessed. In order to interpret the diel changes in both oxygen concentrations and their isotopic ratios, a dynamic model was developed. This model, PoRGy, was successfully applied to the upland boreal reservoirs as well as prairie rivers and ponds. Further, PoRGy was used to understand the interplay between the key parameters that control oxygen concentrations, to compare aquatic ecosystems, to make quantitative estimates of ecosystem metabolism, and to assess the vulnerability of aquatic ecosystems under various environmental stressors. Carbon isotope-mass budgets were used to conclude that community respiration rates declined quickly in the upland reservoirs and had declined by half over five years. This suggested that the most labile organic carbon is quickly consumed but decomposition continued for the five-year life of the project. Net primary production rates were similar for three years, with a small peak in the second or third year, before declining by half by the fifth year. Together, these results indicated that aquatic metabolism slowed over five years while the reservoirs remained a source of greenhouse gases to the atmosphere each year. Net methane production was greatest in the third year of flooding then decreasing by about half by the fifth year. Methane ebullition also peaked in the third year and declined by two-thirds by the fifth year. Together, these results indicated that methanogenesis was greatest in the third year of flooding. The flux of methane to the atmosphere grew in importance relative to that of carbon dioxide over the five years of the experiment. Community respiration and primary production could not be estimated directly from the oxygen isotope-mass budgets since the oxygen respiration enrichment factor remains poorly constrained. Instead, three estimates were made, each based on a different assumption. In general, these estimates suggested that rates of community respiration and primary production decreased slightly for three years and most rapidly in the final two years. The oxygen isotope-mass budgets provided a new method for assessing and constraining community metabolism and greenhouse gas fluxes to the atmosphere. One of the major hypotheses of the whole-ecosystem reservoir experiments was that pre-flood organic carbon stores less tree boles were positively related to greenhouse gas fluxes. Within the three upland boreal forest reservoirs, this hypothesis did not hold true. Over five years, community respiration in the three reservoirs was within 5% of each other. When methane is included, to assess total greenhouse gas fluxes to the atmosphere, the reservoirs were within 1% of each other. Organic carbon stores were therefore poor short-term predictors of carbon lability and greenhouse gas fluxes. This research presented two methods for determining biological rates at the whole-ecosystem scale: one using carbon isotopes and one using oxygen isotopes. Temporal evolution of greenhouse gas cycling within the upland reservoirs was different than in the wetland reservoir and should inform how reservoir development is done vis-à-vis the amount of flooded land of each type versus electricity production. Medium-term estimates of greenhouse gas fluxes suggest that upland reservoirs do not have adequate pre-flood organic carbon stores to sustain elevated levels of decomposition the way wetlands do. The strong evidence of continued production of dissolved organic carbon in the upland reservoirs should concern operators of municipal drinking water reservoirs since elevated dissolved organic carbon can make disinfection difficult.
107

Upių hidrokinetinės energijos gavybos ir aplinkosaugos priemonių integracija / Integration of hydrokinetic river energy production and environmental instruments

Mažeikytė, Ernesta 21 June 2013 (has links)
Magistrantūros studijų baigiamasis darbas 52 lapai, 30 paveikslų, 4 lentelės, 41 literatūros šaltiniai. PAGRINDINIAI ŽODŽIAI: Hidrokinetinė energija, turbinos, nepatvankinė technologija, hidroelektrinė. Tiriamojo darbo objektas: Nepatvankinių technologijų panaudojimas upių hidrokinetinės energijos gavybai. Tiriamojo darbo tikslas: Įvertinti nepatvankinių energijos gavybos technologijų ir aplinkosaugos priemonių integracinius suderinamumus. Tiriamojo darbo uždaviniai: 1. Apžvelgti hidrokinetinės energijos panaudojimo taikant nepatvankines technologijas patirtį užsienio šalyse. 2. Apžvelgti hidrokinetinės energijos taikant nepatvankines technologijas panaudojimo siekius Lietuvoje. 3. Išanalizuoti nepatvankinių technologijų schemas. 4. Išanalizuoti nepatvankinių technologijų poveikį vandens ekosistemoms. 5. Įvertinti galimas nepatvankinių technologijų poveikio vandens ekosistemoms sumažinimo priemones. Tiriamojo darbo metodika: literatūros apžvalgos skyrius rašomas referatyviai, analizuojant mokslinius šaltinius. Duomenys tyrimui renkami analizuojant lietuvišką ir užsienio literatūrą, patentus, schemas, didžiausią dėmesį atkreipiant į nepatvankines energijos gavybos technologijas ir jų poveikį aplinkai. Tiriamojo darbo rezultatai: 1. Literatūros analizėje apžvelgta hidrokinetinės energijos panaudojimo taikant nepatvankines technologijas patirtis Lietuvoje, bei užsienyje. 2. Išanalizuotos nepatvankinių technologijų schemos, bei nepatvankinių technologijų poveikis... [toliau žr. visą tekstą] / The final master work consisting of 52 sheets, 30 images, 4 tables, 41 sources of literature. Key words: hydrokinetic energy, turbines, non-affluent technology, hydroelectric power plant. The object of this work: use of non – affluent technologies in extracting hydrokinetic energy out of the rivers. Main goal of this work: estimate the compatibility between non – affluent energy extracting technologies and tools of environment control integrity. Tasks of this work: 1. Overview of the hydrokinetic energy use abroad applying non – affluent technologies. 2. Overview of the hydrokinetic energy implementation and goals into Lithuanian market. 3. Analyses of the schemes about non – affluent technologies. 4. Analyze the impact of non-affluent technologies to eco systems. 5. Estimate the possible tools for decreasing impact of the non-affluent technologies to water eco systems. Methodology of this work: Literature overview charter is written abstractly analyzing scholarly sources. Data for the research was collected by analyzing Lithuanian and foreign literature, licenses, schemes considering non-affluent energy extraction technologies and their impact to the environment. The results of the work: 1. In literature analysis overviewed the experience of the hydrokinetic energy use applying non-affluent technologies in Lithuania and abroad. 2. Analyzed the schemes of the non – affluent technologies and their impact to the eco systems. 3. Estimating the tools for decreasing impact of the... [to full text]
108

Den urbaniserade Umeälven : Vattenkraftverken som utsträckt urbanisering

Kallerman, Nils January 2015 (has links)
This paper examines the power producing dams along the Ume-river as an integral part of and a result from the urbanization process in Sweden during industrial capitalism. The aim of the paper is to contribute to the knowledge of the urbanization process in Sweden in general and of its traces along the Ume river in the county of Västerbotten in particular. The paper applies the theory of concentrated urbanization and extended urbanization put forward by Neil Brenner and Christian Schmid (2015) and argues that the building of power producing dams along the Ume-river is part of an extended urbanization process. This becomes particularly evident when examining the vast physical structures that is the dams, situated in an otherwise remote and sparsely populated area. These vast physical structures are also very well connected to a nation wide electric grid that has connections to bordering countries as well. Due to neo-liberal developments in Sweden the former state governed electrical market is now deregularized and exposed to corporate competition and capitalist speculation. This paper mainly contributes to the understanding of the urbanization process as a process not only taking place in large urban agglomerations but also affects and shapes by remote areas in physical, social and economic terms.
109

Life in a drawdown zone: natural history, reproductive phenology, and habitat use of amphibians and reptiles in a disturbed habitat.

Boyle, Kelly 08 August 2012 (has links)
Canada is the second highest producer of hydroelectric energy in the world. Nearly 50 of the hydroelectric reservoirs in the country have a capacity larger than 1 billion m3. Despite the great number and extent of hydropower developments in Canada and around the world, relatively little is known about how dams and their operations influence terrestrial and semi-aquatic wildlife. Reservoirs at northern latitudes are characterized by large fluctuations in water level, which create modified shorelines called drawdown zones. To evaluate the impact of these disturbances on amphibians and reptiles, I conducted visual encounter surveys at two sites in the drawdown zone of Kinbasket Reservoir, near Valemount, B.C. From April to August of 2010 and 2011, I documented the habitat use, reproductive phenology, and body condition of two amphibian species (Anaxyrus boreas and Rana luteiventris) as well as the growth, movements, diet, and distribution of one species of garter snake (Thamnophis sirtalis). At two sites in the drawdown zone, A. boreas and R. luteiventris were present for the duration of the summer and utilized several ponds for reproduction. The presence and abundance of Rana luteiventris eggs were generally associated with ponds that had higher mean temperatures, higher mean pH, and the presence of fish. In 2010, there was sufficient time for amphibian breeding and metamorphosis to occur before the reservoir inundated the drawdown zone, but low precipitation levels in that year led to desiccation of many breeding ponds. In 2011, high rainfall and snowmelt led to early inundation of breeding ponds, and thousands of tadpoles were presumably swept into the reservoir. Gravid Thamnophis sirtalis were found at just one of two sites in the drawdown zone, but both sites were frequented by foraging individuals of this species. Anaxyrus boreas appears to be the primary prey of T. sirtalis in the drawdown zone. An improved understanding of how the amphibians and reptiles at Kinbasket Reservoir have persisted in this highly disturbed environment may be vital to their conservation — the activation of a new generating unit at Mica Dam in 2014 will alter the pattern and timing of reservoir inundation for the first time since it was constructed 40 years previously. / Graduate
110

Assessing the impacts of wind integration in the Western Provinces

Sopinka, Amy 06 December 2012 (has links)
Increasing carbon dioxide levels and the fear of irreversible climate change has prompted policy makers to implement renewable portfolio standards. These renewable portfolio standards are meant to encourage the adoption of renewable energy technologies thereby reducing carbon emissions associated with fossil fuel-fired electricity generation. The ability to efficiently adopt and utilize high levels of renewable energy technology, such as wind power, depends upon the composition of the extant generation withinthe grid. Western Canadian electric grids are poised to integrate high levels of wind and although Alberta has sufficient and, at times, an excess supply of electricity, it does not have the inherent generator flexibility required to mirror the variability of its wind generation. British Columbia, with its large reservoir storage capacities and rapid ramping hydroelectric generation could easily provide the firming services required by Alberta; however, the two grids are connected only by a small, constrained intertie. We use a simulation model to assess the economic impacts of high wind penetrations in the Alberta grid under various balancing protocols. We find that adding wind capacity to the system impacts grid reliability, increasing the frequency of system imbalances and unscheduled intertie flow. In order for British Columbia to be viable firming resource, it must have sufficient generation capability to meet and exceed the province’s electricity self-sufficiency requirements. We use a linear programming model to evaluate the province’s ability to meet domestic load under various water and trade conditions. We then examine the effects of drought and wind penetration on the interconnected Alberta – British Columbia system given differing interconnection sizes. / Graduate

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