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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.
611

Atomistic Modelling of Materials for Clean Energy Applications : hydrogen generation, hydrogen storage, and Li-ion battery

Qian, Zhao January 2013 (has links)
In this thesis, a number of clean-energy materials for hydrogen generation, hydrogen storage, and Li-ion battery energy storage applications have been investigated through state-of-the-art density functional theory. As an alternative fuel, hydrogen has been regarded as one of the promising clean energies with the advantage of abundance (generated through water splitting) and pollution-free emission if used in fuel cell systems. However, some key problems such as finding efficient ways to produce and store hydrogen have been hindering the realization of the hydrogen economy. Here from the scientific perspective, various materials including the nanostructures and the bulk hydrides have been examined in terms of their crystal and electronic structures, energetics, and different properties for hydrogen generation or hydrogen storage applications. In the study of chemisorbed graphene-based nanostructures, the N, O-N and N-N decorated ones are designed to work as promising electron mediators in Z-scheme photocatalytic hydrogen production. Graphene nanofibres (especially the helical type) are found to be good catalysts for hydrogen desorption from NaAlH4. The milestone nanomaterial, C60, is found to be able to significantly improve the hydrogen release from the (LiH+NH3) mixture. In addition, the energetics analysis of hydrazine borane and its derivative solid have revealed the underlying reasons for their excellent hydrogen storage properties.  As the other technical trend of replacing fossil fuels in electrical vehicles, the Li-ion battery technology for energy storage depends greatly on the development of electrode materials. In this thesis, the pure NiTiH and its various metal-doped hydrides have been studied as Li-ion battery anode materials. The Li-doped NiTiH is found to be the best candidate and the Fe, Mn, or Cr-doped material follows. / <p>QC 20130925</p>
612

Driving Force and Challenge of Developing Low-Carbon Economy in China

ZHAO, YANG, WU, LEI January 2010 (has links)
With the growth of population and development of the global economy, the unrestrained use of natural and energy resources have seriously influenced environment and economy of world. Many people start to realize the serious environmental problems that come from the high energy utilizations, especially of high carbon dioxide (CO2) emissions. So Low-Carbon Economy has become focus of attention around the world; it also has become every country‟s strategic goals for future development under this global situation.As the biggest country of CO2 emissions in the world, China‟s development of Low-Carbon Economy is increasingly influencing the economy and environmental development in the world, and the country has faced more and more pressure after United Nations Climate Change Conference, 2009. Transition to Low-Carbon Economy is essential road for China, whether respond to the threat of climate change or balance domestic economic development with environmental sustainability. However, China also faces lots of challenges and pressure in the process of transition to Low-Carbon Economy.This thesis combines quantitative method with qualitative methods to do a research about driving force and challenges of developing Low-Carbon Economy in China. Firstly, it discusses the driving forces for China to develop Low-Caron Economy from two aspects-pressures and benefits. Secondly, it investigates challenges that China is likely to face in Low-Carbon Economy development from energy and economic aspect. Finally, it uses cause and effect diagram to explain the bottlenecks of Low-Carbon Economy development in China.Our conclusion is that China faces the bottleneck between challenges and driving force to develop Low-Carbon Economy. And this situation was caused by national actual situations and conditions in China. This explains also why China requested in Copenhagen Conference that “developing countries take appropriated measures to emission control and reduction in terms of receiving the funding and technology support from developed countries. Those emission reduction actions should be done according to the national actual situations and conditions.”
613

Consumer Attitudes towards the Benefits provided by Smart Grid – a Case Study of Smart Grid in Sweden

Christakopoulos, Argiris, Makrygiannis, Georgios January 2012 (has links)
No description available.
614

The Impact of Directive 2009/28/EC on Energy Security and Agricultural Development in Ghana

Preuss, David January 2012 (has links)
The growing demand for biofuels in the European Union is expected to have a significant impact on rural environments in sub-Saharan Africa. In the wake of Directive 2009/28/EC, Ghana experienced a rapid rise in foreign land acquisitions and direct investments to its agricultural sector. The potential implications of this development are multi-fold: While proponents of the EU biofuels policy stress the potential for agricultural development and improved energy security in the region, its opponents criticise the lack of binding rules and regulations concerning social sustainability and indirect land use changes. As a means of assessing the validity of these opposing views, this research paper provides an analysis of the directive's impact on Ghanaian energy security and agricultural development in the country. The analysis is based on key informant interviews and a comprehensive literature reviews. It is concluded that the potential of host countries to generate benefits from the cultivation of energy crops largely rests on their institutional framework. In Ghana, foreign biofuel investments appear to have at least partially resulted in negative socio-economic impacts on local rural communities. Formal and informal land rights, as well as land acquisition procedures present significant obstacles. Civil action and the proposal for a new national biofuels policy indicate, however, that the country could eventually emerge as a beneficiary of the global trend towards biofuels.
615

Sustainable Power Production in Chile

Björnfot, Karl January 2007 (has links)
Summary This report is about how Chile can find its way towards a sustainable power production. The two major Chilean electric systems are modeled and optimized by a special optimization program for energy systems called MODEST. The model is then altered so that new sustainable energy sources can be put into the system. If these new energy sources are more economically beneficial they will enter the system. The time period that is modeled is the years 2006 to 2010 and the demand for electricity is rising between these years. 7 different scenarios where the terms for fossil fuels and renewable energies are changed in different ways is tested to see what can be done to introduce more sustainable energy into the system. The different changes include tax on carbon dioxide emissions, subsidies for new sustainable energy sources and limits in carbon dioxide emissions. The results show that: • Taxes are an ineffective way to get more sustainable energy but can work to reduce emissions. The tax could be used to fund subsidies for cleaner energies. • Subsidies can work to bring in more sustainable energy and if there is a possibility to use the clean development mechanisms available within the Kyoto protocol. Then it does not have to be subsidies but investments from companies in countries that have signed the Kyoto protocol. • Waste to energy is the most cost effective new energy source, although it is questionable however this is really a renewable energy source. The author thinks that although it might not be renewable it is certainly sustainable within a foreseeable future. • A natural gas shortage will have serious effects on the system and should be avoided at least until there are enough alternative fuels available. It is therefore important to continue encourage the development of sustainable power sources. • Carbon dioxide limits could be used in Chile. If they are at reasonable levels they do not need to cost that much and could really help the sustainable energy sources to become more interesting for investors.
616

The Social Acceptance of School-based Solar Photovoltaic Projects: An Ontario, Canada Case Study

Beckstead, Claire Louise January 2008 (has links)
The installation of solar photovoltaic (solar PV) technology on elementary and secondary schools has been undertaken around the world in an attempt to tie together positive environmental action, innovative environmental education, and potential economic gains. In Ontario, the advent of the Renewable Energy Standard Offer Program and the increased focus on environmental education by the Ontario Ministry of Education has resulted in preliminary interest from some Ontario school boards in installing solar PV technology on schools. However, simply installing the technology on school roof-tops does not guarantee that the potential benefits of a school-based solar PV project will be realized. Drawing from the literatures describing the social acceptance of innovation and technology, the social acceptance of renewable energy innovation and technology, and the social acceptance of educational innovation and technology in schools, this thesis attempts to identify non-technical factors that may impede school-based solar PV project development, and ultimately, attempts to identify factors that help maximize potential benefits. The research was conducted in two distinct phases, with the results from Phase 1 informing the focus and design of Phase 2. Phase 1 consisted of nine key-informant interviews with individuals directly involved in school-based solar PV projects in Canada and the United States, and Phase 2 consisted of a case study in the Halton District School Board (HDSB) and the Halton Catholic District School Board (HCDSB) (Ontario, Canada). Both quantitative and qualitative data were collected in Phase 2 through 30 stakeholder interviews and 50 stakeholder surveys. Respondents in the HDSB and HCDSB generally have a positive perception of solar PV technology, but are concerned to some extent about the cost and economic viability of implementing this kind of project. Five funding models for school-based solar PV projects were evaluated by respondents to determine the effect of project funding models on overall project social acceptance. The results show that the project funding model does affect social acceptance, with 78.1% of respondents reporting that at least one of the five models would cause their support for the project to either increase or decrease. Respondents indicated a strong preference for the government/utility model, while the corporate funding model was shown to be the most controversial. This thesis recommends that a broad-based, inclusive, stakeholder-oriented approach to project development could improve trust and communication between project stakeholders, and thus improve the social acceptance for any of the five funding models. Additionally, with any funding model, teacher and administrative support and social acceptance is particularly important to help maximize the educational component of the project.
617

Integrating Planning Theory with Energy Planning in Developing Rural Areas: A Critical Assessment of the Energy Intervention Programs in Rural Hainan, China

Bi, Lei 17 February 2011 (has links)
Energy intervention programs have gained prominence in governmental policies and development agendas as a prevailing practice of improving rural livelihoods and protecting local environment and resources in developing rural areas since early 1970s. In spite of the increasing evidences of small-scale renewable energy systems being advantageous over traditional ones towards rural sustainability, the introduction and diffusion of the new energy systems in many developing rural areas has suffered program ineffectiveness in terms of slow construction, limited utilization, and high risks of being idled or abandoned by the adopters. While there are substantial studies documenting the challenges of rural energy planning, few scholars have devoted to the processes and efficacy of the planning practice. Literature has obvious gaps between planning theory and rural energy planning practice as no prior academic efforts were uncovered to use planning theory to examine the rural energy planning practice and to provide directions to future practice. Meanwhile, literature suggests that the integration of efficacy-oriented and context-dependent principles of planning theory into the energy planning processes can contribute to the effectiveness of rural energy intervention programs. Vital to the integration is the conduct of a study that critically assesses the rural energy planning processes against the insights drawn from planning theory and then provides policy implications for bridging the gaps between theory and practice. A review of literature on energy, planning, and community development in relation to sustainability led to an evaluative framework containing 24 criteria which were aggregated into six groups of principles, i.e., equity, flexibility, efficiency, participation, continuity and reflectivity. The principles were coupled respectively focusing on the operationalization, implementation, and monitoring processes of rural energy planning. Employing a primary case study design, the researcher conducted the field study in southern China’s Hainan province to examine whether the aggregated criteria were upheld and performed in local practices. In the field research, the author collected relative information and data through interviews, surveys, secondary sources, and direct observation. The data were analyzed in a mix of inter-related qualitative and quantitative methods. Where possible, the author used triangulation to limit individual and methodological biases. Hainan’s rural energy intervention programs of introducing and diffusion renewable energy systems such as anaerobic digesters and solar heaters in developing rural areas were significant contents of the provincial eco-village program and eco-province strategy. Although the energy programs had satisfactory effectiveness sporadically in a few villages, the majority of the programs suffered from problems like slow construction, limited utilization, and high risks of being idled or abandoned by the adopters. A number of challenges were recognized and mentioned by the administrative interviewees, including financial, technical, social, cultural, institutional and other constraints that support and conform to the discussions in literature. The study advances the understandings by identifying the gaps between planning theory and local rural energy planning practice in Hainan. Specifically, the equity principle was recognized but not totally fulfilled; the flexibility principle remained contentious and singularly executed; the efficiency principle was accepted but performed without enough scrutiny; the participation principle was emphasized but challenging; the continuity principle was aware of but not compulsorily executed; and the reflectivity principle was vague and overlooked. The author further analyzes that there will be barriers at the micro, meso, and macro levels to impede the integration of planning theory into rural energy planning practice. Extending the findings to a broader discussion on planning for development projects in developing rural areas, the author highlights a number of external and internal problems that harm the program effectiveness and calls for immediate and meaningful attention to ensuring program effectiveness. Several suggestions are provided for policy reconsideration and reorientation.
618

Large-scale Solar PV Investment Planning Studies

Muneer, Wajid January 2011 (has links)
In the pursuit of a cleaner and sustainable environment, solar photovoltaic (PV) power has been established as the fastest growing alternative energy source in the world. This extremely fast growth is brought about, mainly, by government policies and support mechanisms world-wide. Solar PV technology that was once limited to specialized applications and considered very expensive, with low efficiency, is becoming more efficient and affordable. Solar PV promises to be a major contributor of the future global energy mix due to its minimal running costs, zero emissions and steadily declining module and inverter costs. With the expanding practice of managing decentralized power systems around the world, the role of private investors is increasing. Thus, the perspective of all stakeholders in the power system, including private investors, has to be considered in the optimal planning of the grid. An abundance of literature is available to address the central planning authority’s perspective; however, optimal planning from an investor’s perspective is not widely available. Therefore, this thesis focuses on private investors’ perspective. An optimization model and techniques to facilitate a prospective investor to arrive at an optimal investment plan in large-scale solar PV generation projects are proposed and discussed in this thesis. The optimal set of decisions includes the location, sizing and time of investment that yields the highest profit. The mathematical model considers various relevant issues associated with PV projects such as location-specific solar radiation levels, detailed investment costs representation, and an approximate representation of the transmission system. A detailed case study considering the investment in large-scale solar PV projects in Ontario, Canada, is presented and discussed, demonstrating the practical application and usefulness of the proposed methodology and tools.
619

Modelling of a Natural-Gas-Based Clean Energy Hub

Sharif, Abduslam January 2012 (has links)
The increasing price of fuel and energy, combined with environmental laws and regulations, have led many different energy producers to integrate renewable, clean energy sources with non-renewable ones, forming the idea of energy hubs. Energy hubs are systems of technologies where different energy forms are conditioned and transformed. These energy hubs offer many advantages compared to traditional single-energy sources, including increased reliability and security of meeting energy demand, maximizing use of energy and materials resulting in increasing the overall system efficiency. In this thesis, we consider an energy hub consisting of natural gas (NG) turbines for the main source of energy— electricity and heat— combined with two renewable energy sources—wind turbines and PV solar cells. The hub designed capacity is meant to simulate and replace the coal-fired Nanticoke Generating Station with NG-fired power plant. The generating station is integrated with renewable energy sources, including wind and solar. The hub will also include water electrolysers for hydrogen production. The hydrogen serves as an energy storage vector that can be used in transportation applications, or the hydrogen can be mixed into the NG feed stream to the gas turbines to improve their emission profile. Alkaline electrolysers’ technology is fully mature to be applied in large industrial applications. Hydrogen, as an energy carrier, is becoming more and more important in industrial and transportation sectors, so a significant part of the thesis will focus on hydrogen production and cost. In order to achieve the goal of replacing the Nanticoke Coal-fired Power Plant by introducing the energy hub concept, the study investigates the modeling of the combined system of the different technologies used in terms of the total energy produced, cost per kWh, and emissions. This modeling is done using GAMS® in order to make use of the optimization routines in the software. The system is modeled so that a minimum cost of energy is achieved taking into account technical and thermodynamic constrains. Excess energy produced during off-peak demand by wind turbines and PV solar cells is used to feed the electrolyser to produce H2 and O2. Through this method, a significant reduction in energy cost and greenhouse gas (GHG) emissions are achieved, in addition to an increased overall efficiency.
620

Voltage Stability Analysis with High Distributed Generation (DG) Penetration

Al-Abri, Rashid 03 August 2012 (has links)
Interest in Distributed Generation (DG) in power system networks has been growing rapidly. This increase can be explained by factors such as environmental concerns, the restructuring of electricity businesses, and the development of technologies for small-scale power generation. DG units are typically connected so as to work in parallel with the utility grid; however, with the increased penetration level of these units and the advancements in unit’s control techniques, there is a great possibility for these units to be operated in an autonomous mode known as a microgrid. Integrating DG units into distribution systems can have an impact on different practices such as voltage profile, power flow, power quality, stability, reliability, and protection. The impact of the DG units on stability problem can be further classified into three issues: voltage stability, angle stability, and frequency stability. As both angle and frequency stability are not often seen in distribution systems, voltage stability is considered to be the most significant in such systems. In fact, the distribution system in its typical design doesn’t suffer from any stability problems, given that all its active and reactive supplies are guaranteed through the substation. However, the following facts alter this situation: • With the development of economy, load demands in distribution networks are sharply increasing. Hence, the distribution networks are operating more close to the voltage instability boundaries. • The integration of distributed generation in distribution system introduces possibility of encountering some active/reactive power mismatches resulting in some stability concerns at the distribution level. Motivated by these facts, the target of this thesis is to investigate, analyze and enhance the voltage stability of distribution systems with high penetration of distributed generation. This study is important for the utilities because it can be applied with Connection Impact Assessment (CIA ). The study can be added as a complement assessment to study the impacts of the installation of DG units on voltage stability. In order to accomplish this target, this study is divided into three perspectives: 1) utilize the DG units to improve the voltage stability margin and propose a method to allocate DG units for this purpose, 2) investigate the impact of the DG units on proximity to voltage stability 3) conduct harmonic resonance analysis to visualize the impacts of both parallel and series resonance on the system’s stability. These perspectives will be tackled in Chapter 3, Chapter 4, and Chapter 5, respectively. Chapter 3 tackles placing and sizing of the DG units to improve the voltage stability margin and consider the probabilistic nature of both the renewable energy resources and the load. In fact, placement and sizing of DG units with an objective of improving the voltage stability margin while considering renewable DG generation and load probability might be a complicated problem, due to the complexity of running continuous load flow and at the same time considering the probabilistic nature of the load and the DG unit’s resources. Therefore, this thesis proposes a modified voltage index method to place and size the DG units to improve the voltage stability margin, with conditions of both not exceeding the buses’ voltage, and staying within the feeder current limits. The probability of the load and DG units are modeled and included in the formulation of the sizing and placing of the DG units. Chapter 4 presents a model and analysis to study the impact of the DG units on proximity to voltage instability. Most of the modern DG units are equipped with power electronic converters at their terminals. The power electronic converter plays a vital role to match the characteristics of the DG units with the requirements of the grid connections, such as frequency, voltage, control of active and reactive power, and harmonic minimization. Due to the power electronics interfacing, these DG units have negligible inertia. Thus, they make the system potentially prone to oscillations resulting from the network disturbances. The main goal of this chapter is to model and analyze the impact of distributed generation DG units on the proximity of voltage instability, with high penetration level of DG units. Chapter 5 studies the harmonic resonance due to the integration of DG units in distribution systems. Normally, the harmonic resonance phenomenon is classified as a power quality problem, however, this phenomenon can affect the stability of the system due to the parallel and series resonance. Thus, the main goal of this chapter is to study and analyze the impact of the integration of distributed generation on harmonic resonance by modeling different types of DG units and applying impedance frequency scan method.

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