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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.
191

Single-stage single-switch power factor correction circuits : analysis, design and implementation

Wei, Huai 01 January 1999 (has links)
No description available.
192

The prospects for conventional and renewable energy in the context of African economies

Stauss, Wolfgang 03 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: Energy of any form is of paramount importance in the development process of communities, regions and nations. It is a domestic necessity but also a factor of production whose cost directly affects prices of other goods and services, and the competitiveness of enterprises. Energy also plays a critical role in enabling social improvement and development: economies that are unable to provide access to modem energy for everyone at reasonable costs are left behind in a globalised world. Industrialised countries have proved that efficient energy production and distribution is a key factor for the generation of wealth. They have built there success on energy sources that are easily accessible and convertible into motion, heat or electricity. However, most of these sources are limited and not renewable in the literal meaning of the word. Huge infrastructure projects and trillion dollar investments are done in energy sources like fossil fuels that will in a not too distant future be exhausted. Additionally, these fuels lead to climate change with unpredictable consequences. Renewable energy on the other hand, has not been given enough political and financial attention that would make it competitive and provide a real alternative. Developing countries, and the African continent as a whole, have tried to imitate the economies of the first world when it comes to energy sourcing. They are very likely to fall into the same traps: large investments into projects that benefit a small number of people, over capacities on the supply side, energy generation that is closely connected to environmental pollution and last but not least: dependency on energy reserves that are located in politically unstable regions of the world. It is recommended that Africa as a continent should work on energy sourcing concepts that • reduce poverty and enable development, • give its scattered population access to modern energy at reasonable cost, • rely on socially and environmentally sustainable energy generation, • integrate regions to avoid conflicts, • lead to independency from external energy supply and • make the continent a competitive actor in the global market place. In the case of 3 African countries namely Algeria, Ghana and South Africa it is illustrated that there is an opportunity for Africa to do things differently and to learn from the mistakes in the history of modem energy. The focus on existing opportunities, the interest to learn from others and the readiness to work together with partners enable these nations to really fuel development and achieve above average social and economical growth. / AFRIKAANSE OPSOMMING: Energie in alle vorme is van uiterste belang in die ontwikkeiingsproses van gemeenskappe, streke en nasies. Dit is beide 'n plaaslike vereiste, maar ook 'n produksiefaktor, waarvan die koste 'n direkte invloed het op pryse van ander goedere en dienste en die mededingendheid van ondernemings. Ekonomië wat nie die vermoe het om toegang na moderne energie vir almal teen redelike koste te gee nie, word agtergelaat in 'n geglobaliseerde wereld. Geindustrialiseerde lande het bewys dat effektiewe energieproduksie en -verspreiding 'n sleutelfaktor is vir welvaartskepping. Hulle sukses is gebou op energiebronne wat maklik, toeganklik en omskakelbaar is in beweging, hitte of elektrisiteit. Meeste van hierdie bronne is egter beperk en nie hernubaar nie. Enorme infrakstuktuurprojekte van biljoene dollar word investeer in energiebronne soos fossielbrandstof wat in die nie-soverre-toekoms uitgeput sal wees. Die gebruik van hierdie tipe brandstof lei tot klimaatsveranderinge met onvoorspelbare gevolge. Hernubare energie het egter nog nie genoegsame politieke en finansiele steun gekry wat dit 'n mededingende werklike alternatief maak nie. Ontwikkelende lande en Afrika as geheel, probeer eerste wereldse ekonomie navolg ten opsigte van energie verkryging. Die kanse is goed dat hulle in die volgende slaggate sal val: Groot investering wat min mense bevoordeel; oorvoorsiening ten opsigte van lewering; energie-opwekking wat omgewingsbesoedeling aan die hand werk; afhanklikheid van energie-reserwes wat in politiese onstabiele streke van die wereld gelee is. Dit word aanbeveel dat die Afrika-kontinent werk na energiebron konsepte wat: • Verminderde armoede aan die hand werk en ontwikkeling bevorder • 'n Verspreide bevolking toegang gee tot moderne energie teen billike pryse • Vertrou op sosiaal en omgewings volhoubare energie opwekking • Streke integreer ten einde konflik te vermy • Afhanklikheid van eksterne energie bronne vermy • Die kontinent 'n mededingende speler in die wereldmark, maak. In die gevalle van drie Afrika lande naamlik, Algerie, Ghana en Suid-Afrika, is dit geillustreer dat daar is 'n geleentheid vir Afrika om nie die foute van die verlede te herhaal nie. Die fokus op bestaande geleenthede, die belangstelling om te leer van andere en die bereidwilligheid om saam met vernote te werk, skep die geIeentheid vir hierdie lande om ontwikkeling te dryf en om bo-gemiddelde ekonomiese en sosiale groei aan te teken.
193

A critical assessment of the economic viability of liquefied natural gas (LNG) as a competitive source of energy : what are the implications for South Africa?

Hoosain, Nazier 12 1900 (has links)
Thesis (MBA (Business Management))--University of Stellenbosch, 2009.
194

The impact of national oil companies on the energy security of OECD countries

Munro, Hugh M. January 2012 (has links)
National oil companies (NOCs) control over 80 percent of world oil reserves and over 50 percent of gas reserves and hold exclusive rights to exploration and development of oil and gas reserves within their home countries. Because of host government involvement and supervision, NOCs may also act as instruments of state, implementing government foreign and domestic policies such as wealth re-distribution through the provision of subsidised oil products, job creation, and economic development. Such activities can lead to restricted availability of funds for finding and developing reserves for future production and to inefficiencies in current production and distribution. This thesis assesses the geopolitical factors that influence the conduct, strategies and priorities of NOCs and how these may impact on the continuing security of energy supplies to countries which are members of the Organisation for Economic Co-operation and Development (OECD). It will focus on ten NOCs supplying oil to world markets and two which supply gas to the European market. The study will also review the activities and .scope for influence as state instruments of Sovereign Wealth Funds which have been established by states with NOCs, in particular, those which have earned substantial petro-dollar surpluses, during the period of high oil and gas prices of2006-2008. In an age of global interdependence between nations, specific objectives of this thesis are to consider the implications of anticipated growth in world demand for oil and gas supplies over the next 20 years, whether world production capacity is likely to grow to meet increases in world demand, the potential impact on world oil and gas supplies of the policies and practices of NOCs, in particular, the desire of host governments to require NOCs to follow non- commercial objectives, and the responses from OECD countries to threats to their energy security from potential restrictions on supplies.
195

A survey on the state of energy efficiency adoption and related challenges amongst selected manufacturing SMMEs in the Booysens area of Johannesburg

26 June 2015 (has links)
M.A. (Environmental Management) / The Small Micro Medium Enterprise (SMME) sector plays a critical role in the economy of South Africa by reducing poverty and providing employment. South Africa has about 6 million SMMEs that employ more than 61% of citizens and contribute about 37% to the Gross Domestic Product (GDP). The growth and development of the sector over the years has however been compromised and threatened by the shortage of electricity and increasing electricity tariffs. Whereas large companies can manage to afford the adoption of energy efficiency measures in order to reduce energy costs, SMMEs have limited resources and may therefore struggle to afford energy efficiency adoption. However, there is a lack of scientific documentation about energy efficiency adoption amongst manufacturing SMMEs (M-SMMEs) in South Africa. The purpose of the research is to therefore assess the state of energy efficiency adoption amongst M-SMMEs, despite the challenges they experience. To achieve this research goal, the study surveyed and characterised the extent of energy efficiency adoption and also unveiled the drivers and barriers to energy efficiency adoption. Data were collected by means of surveys, making use of questionnaires. A sample of 30 firms was selected for the research. Almost all (96%) firms perceived EE as an opportunity. However, only 50% had adopted EE measures. Key drivers to adoption included the motive to reduce production costs, mitigate the impact of increasing electricity prices, gain competitive advantage and payback period. The gap between EE perception and adoption was caused by several barriers like the lack of finance, skills and time. Among non-adopters, 60% indicated their willingness to be trained in EE. The study therefore recommends improved capacity building through workshops for M-SMMEs.
196

Essays on Development Economics and Energy Access

Yoon, Semee January 2015 (has links)
This thesis makes contributions to provide the microeconomic evidence on the effects of electricity provision and on the feasibility of electricity provision via renewable energy in developing countries. Three selected topics are presented. First, we discuss how the impact of national electricity grid provision affects household welfare and individual labor activities in Vietnam. To overcome the endogeneity problem of infrastructure provision, the slope of the terrain is used as the instrumental variable. We present both first-difference regression and pooled regression results using household survey data and geographic datasets. The effect of electrification on female labor supply is negative, contrary to the evidence suggested in the previous literature. Second, we measure willingness to pay for solar lanterns among the poor rural households in India using the Becker-DeGrook-Marschak method. We conduct field surveys to evaluate the effectiveness of providing a trial period and postponed payment scheme to promote sales. Results show that willingness to pay for the solar product among the consumers is low. Lastly, we report patterns of awareness and interest in solar home systems (SHS) among the poor rural households in India. Results show that willingness to pay for SHS is low, even if the national subsidy is taken into account. Moreover, households that have experience using grid electricity have greater willingness to pay for SHS.
197

Methods for Analysis of Urban Energy Systems: A New York City Case Study

Howard, Bianca Nichole January 2016 (has links)
This dissertation describes methods developed for analysis of the New York City energy system. The analysis specifically aims to consider the built environment and its' impacts on greenhouse gas (GHG) emissions. Several contributions to the urban energy systems literature were made. First, estimates of annual energy intensities of the New York building stock were derived using a statistical analysis that leveraged energy consumption and tax assessor data collected by the Office of the Mayor. These estimates provided the basis for an assessment of the spatial distribution of building energy consumption. The energy consumption estimates were then leveraged to estimate the potential for combined heat and power (CHP) systems in New York City at both the building and microgrid scales. In aggregate, given the 2009 non-baseload GHG emissions factors for electricity production, these systems could reduce citywide GHG emissions by 10%. The operational characteristics of CHP systems were explored further considering different prime movers, climates, and GHG emissions factors. A combination of mixed integer linear programing and controlled random search algorithms were the methods used to determine the optimal capacity and operating strategies for the CHP systems under the various scenarios. Lastly a multi-regional unit commitment model of electricity and GHG emissions production for New York State was developed using data collected from several publicly available sources. The model was used to estimate average and marginal GHG emissions factors for New York State and New York City. The analysis found that marginal GHG emissions factors could reduce by 30% to 370 g CO₂e/kWh in the next 10 years.
198

Problems of the fossil-energy economy and the possible implications of alternative energy sources for planning future Australian settlements

Hume, David Edward. January 1978 (has links) (PDF)
Includes bibliographical references (p. 165-188)
199

Investigation of the environmental impact of wind energy and supplemental energy systems using a life cycle approach

Prempreeda, Preedanood 30 August 2012 (has links)
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
200

En pluralistisk maktordning? : om pensionärsorganisationernas politiska inflytande

Feltenius, David January 2004 (has links)
In 1991, the Swedish Social Democratic government established the Pensioners’ Council at the Ministry of Social Affairs. The Council’s purpose and structure were spelled out by the Government in a Commission of Inquiry Directive. According to this, the Council is to be a forum for deliberations between the Government and pensioners’ organizations. At the municipal level, Senior Citizens Councils have existed since the 1970s. They fill a similar purpose to that of the Pensioners’ Council at the central level, namely to be an arena for political discussions between representatives from pensioners’ organizations and the municipality. The purpose of this dissertation is two-fold. First, I describe the influence of pensioners’ organizations on the establishment of the pensioners’ councils and their political influence – potential as well as actual – in these councils. Second, I seek to explain the influence of pensioners’ organizations from a power resources perspective. By doing so, I hope to contribute to our knowledge of the relationship between the welfare state and organized interests. Does this relationship imply the existence of a corporatist or pluralistic power structure? Finally, I also hope to contribute to our understanding of the future development of the welfare state in the light of a global economy and aging population. The empirical investigation on the central level suggests that pensioners’ organizations influenced the decision to establish the Pensioners’ Council. Moreover, they had actual as well as potential political influence through the council since the early 1990s. There success in influencing government policy is due to the fact that pensioners’ organizations represent an important voting group and their employees have expert knowledge. At the local level, the empirical investigation suggests that pensioners’ organizations had influence on decisions made by municipalities to establish Senior Citizens Councils. However, opportunities to influence vary at the local level, and pensioners’ organizations actual political influence is limited. This limited influence can be explained as a consequence of pensioners’ organizations lack of an important power resource at the local level – employed expertise. It is argued in the dissertation that the empirical results do not suggest an existence of a corporatist power structure in social issues. Rather, they point to a pluralistic power structure – i.e. along side producer organizations, other organizations (such as those for welfare consumers) also have an important power position. This, in turn, limits the ability of politicians to cut welfare spending. The case of pensioners’ organizations therefore suggests that we cannot expect any drastic downsizing of the Swedish welfare state due to factors such as the globalization of the economy. In light of the aging population, the empirical results suggest that politicians will have to seek other solutions to be able to meet the challenge of financing welfare programs targeting the elderly than making drastic cutbacks in those programs.

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