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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.
461

Developing an understanding of the drivers of bat activity patterns relevant to wind turbines

Thwaits, Tiffany Edan January 2014 (has links)
The increasing number of proposed wind farm developments in South Africa provides an immediate reason to assess bat activity and diversity, with the expectation of developing measures to mitigate for negative impacts. The overall aim of this thesis was contribute to an understanding of the drivers of bat activity, relevant to wind turbines, and to determine what factors (exogenous – environmental, or endogenous – intrinsic physiological processes) contributed to observed bat activity patterns, at the Metrowind Van Stadens Wind Farm in the Eastern Cape of South Africa. A combination of active (mist netting) and passive (acoustic) bat monitoring techniques were used to determine free-ranging bat activity patterns (Chapter 3). A total of 889 bat passes were recorded over 323 detector nights from the beginning of May 2012 to the end of December 2012. The Cape serotine bat (82 per cent) and the Egyptian free-tailed bat (97 per cent) made up the majority of all bat passes recorded on site. Large variations in bat activity per month and per hour were apparent, with bat activity peaking in May 2012 and during the first few hours after sunset (18:00-23:00). Patterns in nightly, free-ranging bat activity at the site were modelled against various environmental conditions. Month, temperature, wind speed and an interaction between month and rainfall were the most significant predictors of bat activity, explaining 80 per cent of the variation observed on free-ranging bat activity patterns. A total of eight Cape serotine bats (Table 4.1.) were caught in mist nets on site and changes in the resting metabolic rate (RMR) of torpid (n = 6), and normothermic (n = 2) bats, over a 24 hr period, were measured and used to predict free-ranging Cape serotine bat activity (Chapter 4). Cape serotine bats showed a high proclivity for torpor in the laboratory and peaks in RMR were observed at 18:00 (0.89 ± 0.95 VO2 mℓ.g-1.hr-1) and again from 20:00-21:00 (0.89 ± 0.91 VO2 mℓ.g-1.hr-1). Peaks in RMR of torpid individuals coincided with peaks in the average hourly free-ranging activity of the Cape serotine bat, and RMR explained 33 per cent of the variation and was a good predictor of free-ranging bat activity (R2 = 0.2914). This study showed that both exogenous (Chapter 3) and endogenous (Chapter 4) factors drive bat activity in the wild. Although this dissertation was not intended for wind turbine management, the information presented on the biology and activity of bats is important for managing interactions between bats and wind turbines. By determining what factors influence bat activity, we are able to predict when bats will be most active and thus can develop mitigation measures to reduce the potential impacts that wind turbines will have on the bat community. In order to conserve bats and reduce potential bat fatalities from occurring at the site, mitigation measures should be concentrated to those times when bats are most active (May and during the first few hours after sunset – 18:00 to 22:00).
462

Farma větrných elektráren Mauricius / Complex of wind power plants Mauricius

Trykarová, Štěpánka January 2009 (has links)
This diploma thesis evaluates the present standing of the wind energy in the Czech republic and in the world. It targets the results of new installed wind power stations to the economy. It ilustrates the preparation procedure. It shows the reasons why to invest to the wind energy. It is concerned with the question, if the building-up of wind power plant has the perspective of economic efficiency. It points out the effect on the environment and health.
463

Localising suitable areas for wind power development in Kiruna Municipality. : A spatial multi-criteria decision analysis.

Marcianò, Pietro January 2017 (has links)
Within the last decade, wind power has faced a strong expansion in Sweden, supported by national policies. However, when wind power projects are to be developed, a series of legal difficulties, opposing land-use interests and resistance often arise, hindering their implementation on a local level. To bypass such difficulties, the Swedish government has invited municipalities to localise suitable areas for wind power development in their comprehensive plans. By adopting this proactive approach, different interests and views can be implemented in an early stage of the planning process, possibly reducing the risk of land-use issues and local resistance.The Municipality of Kiruna is currently updating its comprehensive plan and wind power is among the planning issues to be further investigated. Therefore, this thesis aims to combine GIS and multi-criteria decision making to support wind power spatial planning in Kiruna Municipality by exploring environmental, economic and social constraints and criteria under different planning scenariosTherefore, a spatial multi-criteria decision analysis is implemented to promote wind power localisation and at the same time, to prevent possible detrimental consequences. Swedish legislation, guidelines issued by national agencies and wind power planning practices are implemented to delimit areas feasible or unfeasible for wind power development. Then, the localisation process within feasible areas is guided by a set of social, economic and environmental criteria reflecting land-use interests typical of Kiruna Municipality. Weights, steering the relevance of the different criteria in the process, are then developed on the basis of three planning scenarios of future development for the Nordic Arctic.The results of the analysis show that approximately 90% of the territory of Kiruna Municipality is not feasible for wind power development. In particular, low wind speeds and areas of interest for defence are constraints excluding large portions of the municipal territory. Among the feasible areas, it is particularly complex to identify locations which are not located within areas of interest for reindeer herding or national interest for undisturbed mountainous environment and that have an adequate distance from existing electric grids. Nevertheless, the planning scenarios pinpoint suitable locations for wind power development in northeastern Kiruna, in proximity of Karesuando.
464

Podnikatelský plán: Výstavba větrné elektrárny / Business Plan: Construction of wind farms

Malaníková, Pavlína January 2015 (has links)
The aim of this thesis will be to develop a business plan for the construction of wind turbines. There are described steps that are necessary to consider when setting up a business such as a description of the legislative environment, peer and risk analysis. Other objectives of the study is to provide technical, financial and business information that is important to evaluate the project in terms of its implementation or rejection. In this thesis will be processed budgets on the basis shall be calculated capital expenditures and cash income from investments (cash flow).
465

Control of distributed generation and storage : operation and planning perspectives

Alnaser, Sahban Wa'el Saeed January 2015 (has links)
Transition towards low-carbon energy systems requires an increase in the volume of renewable Distributed Generation (DG), particularly wind and photovoltaic, connected to distribution networks. To facilitate the connection of renewable DG without the need for expensive and time-consuming network reinforcements, distribution networks should move from passive to active methods of operation, whereby technical network constraints are actively managed in real time. This requires the deployment of control solutions that manage network constraints and, crucially, ensure adequate levels of energy curtailment from DG plants by using other controllable elements to solve network issues rather than resorting to generation curtailment only. This thesis proposes a deterministic distribution Network Management System (NMS) to facilitate the connections of renewable DG plants (specifically wind) by actively managing network voltages and congestion in real time through the optimal control of on-load tap changers (OLTCs), DG power factor and, then, generation curtailment as a last resort. The set points for the controllable elements are found using an AC Optimal Power Flow (OPF). The proposed NMS considers the realistic modelling of control by adopting one-minute resolution time-series data. To decrease the volumes of control actions from DG plants and OLTCs, the proposed approach departs from multi-second control cycles to multi-minute control cycles. To achieve this, the decision-making algorithm is further improved into a risk-based one to handle the uncertainties in wind power throughout the multi-minute control cycles. The performance of the deterministic and the risk-based NMS are compared using a 33 kV UK distribution network for different control cycles. The results show that the risk-based approach can effectively manage network constraints better than the deterministic approach, particularly for multi-minute control cycles, reducing also the number of control actions but at the expense of higher levels of curtailment. This thesis also proposes energy storage sizing framework to find the minimum power rating and energy capacity of multiple storage facilities to reduce curtailment from DG plants. A two-stage iterative process is adopted in this framework. The first stage uses a multi-period AC OPF across the studied horizon to obtain initial storage sizes considering hourly wind and load profiles. The second stage adopts a high granularity minute-by-minute control driven by a mono-period bi-level AC OPF to tune the first-stage storage sizes according to the actual curtailment. The application of the proposed planning framework to a 33 kV UK distribution network demonstrates the importance of embedding real-time control aspects into the planning framework so as to accurately size storage facilities. By using reactive power capabilities of storage facilities it is possible to reduce storage sizes. The combined active management of OLTCs and power factor of DG plants resulted in the most significant benefits in terms of the required storage sizes.
466

Real options theory applied to renewable energy generation projects planning

Martinez-Cesena, Eduardo Alejandro January 2012 (has links)
The existing environmental threats and the ever increasing global dependence on electric power highlight the importance of producing power in a sustainable manner. In accordance, it is vital to attract investments in electricity generation projects based on renewable energy sources, also called renewable energy projects (REP). This poses a challenge, as REP tend to be less financially competitive than their fossil fuel based counterparts. Moreover, the power grid has to be upgraded to integrate large amounts of RESs in an efficient and economic manner. An appealing alternative to enhance the financial appealing of REP is to improve the techniques used for their assessment. These tools produce robust and economically sound assessments, but tend to undervalue REP and other projects under uncertainty, as they neglect the flexibility of the projects to be adjusted in response to uncertainty. This can be corrected by extending the tools with the aid of real options (RO) theory. RO theory can be used to extend assessment techniques to value flexibility derived from the projects, their management, and even their environment, which can be used to enhance the financial value of REP in the changing power sector. In addition, the scope of RO theory is increasing to address flexibility in the design of the projects. Therefore, the theory can drive investments in REP and motivate the design of more profitable projects. This research project seeks to analyse the potential of RO theory to increase the financial worth of different types of REP in the current and changing power sector. The novelties of this research are that it expands RO theory by addressing the flexibility within the design of the projects, the potential of RO theory to manage uncertainties that are exclusive to the projects or typical in the power sector, and other relevant areas of research interest. The research produced several RO methodologies to model the planning, operation, and design of hydropower projects, wind power projects, and solar photovoltaic projects in existing power sector environments and environments characterised by high penetration of RESs and consumers with demand response capabilities. The results demonstrate the applicability of RO theory to enhance the financial value of different types of REP under a wide range of circumstances.
467

Analýza dopadů větrné energie na hospodaření ČEPSu a dopad rozvojových investic firmy ČEPS na českou ekonomiku / Analysis of the impact of electricity generation from wind on investment activities of CEPS’s company, assessment of the impact of these investments on the Czech economy

Krchová, Eva January 2014 (has links)
The aim of master thesis is to analyze the impact of electricity generation from wind on investment activities of CEPS's company, and also to assess the impact of these investments on the Czech economy. The work familiarizes readers with reasons for the development of the transmission system in the Czech Republic, with the concept of blackout and also with apparatus of assessing the impact of investment on the economy of the selected state -- input-output model analysis. The method used to obtain data for this work is based on the literature review, as well as expert advice on the input-output model, consultation with the experts in CEPS and the data provided by them. The theoretical part deals with Czech transmission system, and it is followed by the development of wind energy construction and the problems associated with it, with blackout and readiness of the Czech Republic to the possible failure in electricity supply. In the practical part, there are measures that are built in order to prevent the risk of blackouts in the Czech Republic, there is a more detailed examination of the Plan of development and rehabilitation of Czech transmission system, and there is also described the process of construction of analytical input-output apparatus for analyzing the impact of CEPS's development investments on the Czech economy, approximated by GDP.
468

Stochastic Optimal Control of Renewable Energy

Caballero, Renzo 30 June 2019 (has links)
Uruguay is a pioneer in the use of renewable sources of energy and can usually satisfy its total demand from renewable sources. Control and optimization of the system is complicated by half of the installed power - wind and solar sources - be- ing non-controllable with high uncertainty and variability. In this work we present a novel optimization technique for efficient use of the production facilities. The dy- namical system is stochastic, and we deal with its non-Markovian dynamics through a Lagrangian relaxation. Continuous-time optimal control and value function are found from the solution to a sequence of Hamilton-Jacobi-Bellman partial differential equations associated with the system. We introduce a monotone scheme to avoid spurious oscillations in the numerical solution and apply the technique to a number of examples taken from the Uruguayan grid. We use parallelization and change of variables to reduce the computational times. Finally, we study the usefulness of extra system storage capacity offered by batteries.
469

Climate Change Effects on Electricity Generation from Hydropower, Wind, Solar and Thermal Power Plants

January 2020 (has links)
abstract: Climate change is affecting power generation globally. Increase in the ambient air temperature due to the emission of greenhouse gases, caused mainly by burning of fossil fuels, is the most prominent reason for this effect. This increase in the temperature along with the changing precipitation levels has led to the melting of the snow packs and increase in the evaporation levels, thus affecting hydropower. The hydropower in the United States might increase by 8%-60% due to Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 scenarios respectively by 2050. Wind power generation is mainly affected by the change in the wind speed and solar power generation is mainly affected by the increase in the ambient air temperature, changes in precipitation and solar radiation. Solar power output reduces by approximately a total of 2.5 billion kilowatt- hour (kWh) by 2050 for an increase in ambient air temperature of 1 degree Celsius. Increase in the ambient air and water temperature mainly affect the thermal power generation. An increase in the temperature as per the RCP 4.5 and RCP 8.5 climate change scenarios could decrease the total thermal power generation in the United States by an average of 26 billion kWh and a possible income loss of around 1.5 billion dollars. This thesis discusses the various effects of climate change on each of these four power plant types. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2020
470

Methodology for Identifying Inverter-based Renewable Generation Penetration Threshold in a Power System

January 2020 (has links)
abstract: Energy is one of the wheels on which the modern world runs. Therefore, standards and limits have been devised to maintain the stability and reliability of the power grid. This research shows a simple methodology for increasing the amount of Inverter-based Renewable Generation (IRG), which is also known as Inverter-based Resources (IBR), for that considers the voltage and frequency limits specified by the Western Electricity Coordinating Council (WECC) Transmission Planning (TPL) criteria, and the tie line power flow limits between the area-under-study and its neighbors under contingency conditions. A WECC power flow and dynamic file is analyzed and modified in this research to demonstrate the performance of the methodology. GE's Positive Sequence Load Flow (PSLF) software is used to conduct this research and Python was used to analyze the output data. The thesis explains in detail how the system with 11% of IRG operated before conducting any adjustments (addition of IRG) and what procedures were modified to make the system run correctly. The adjustments made to the dynamic models are also explained in depth to give a clearer picture of how each adjustment affects the system performance. A list of proposed IRG units along with their locations were provided by SRP, a power utility in Arizona, which were to be integrated into the power flow and dynamic files. In the process of finding the maximum IRG penetration threshold, three sensitivities were also considered, namely, momentary cessation due to low voltages, transmission vs. distribution connected solar generation, and stalling of induction motors. Finally, the thesis discusses how the system reacts to the aforementioned modifications, and how IRG penetration threshold gets adjusted with regards to the different sensitivities applied to the system. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2020

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