Thesis (M.Tech.: Civil Engineering)-Dept. of of Civil Engineering and Surveying, Durban Institute of Technology, 2005 xii, 89 leaves : ill. ; 30 cm / The Reconstruction and Development Programme adopted by the Government of National Unity is more than a list of the services required to improve the quality of life of the majority of South Africans. It is not just a call for South Africans to unite to build a country free of poverty and misery; it is a programme designed to achieve this objective in an integrated and principled manner. Based on the strategic objectives, as highlighted in the White Paper on Water Supply and Sanitation Policy, with regard to alleviating the chronic potable water shortages in South Africa, this thesis investigates a design methodology to supply potable water through the use of wind energy. The design focuses on small rural off-grid developments where grid electricity either has not or will not reach, and where renewable energy is the only viable option. This thesis provides an overview of wind energy and presents the fundamentals of wind power calculations. It also formulates an overview of the historic and present situation with regards to potable water supply, and reflects on the need for urgent intervention. The feasibility of using wind energy to supply potable water to rural communities in South Africa is explored in a case study. The various problem areas are identified and examined and a wide range of possible solutions are recommended. A final flow chart for the system design is proposed, thus ensuring comprehensive design methodology from which future design of similar systems can be based.

Developing renewable alternatives for energy production is one of the main methods for climate change mitigation and sustainable development. As the key component in permanent magnets, neodymium is considered as one of the most critical elements in the rare earth family in the development of modern society. It plays a significant role in increasing efficiency and reducing weight in many applications like hard disc drives, audio equipment, direct- driven gearless and conventional wind turbine design, as well as electric vehicles designs with NiMH batteries. The emerging problem of neodymium production is the peak neodymium issue, which implies a potential risk of supply in the future due to the unsustainable production pathway. Now, China is producing more than 90% of the rare earth elements with an around 40% reserves and is facing severe problems of environmental pollution, smuggling, and increasing domestic demand. This paper makes efforts to see if the risk of supply would constrain future wind power development with a special focus on the China’s dominance in production and policies. By fitting historic production data with three curve models (logistic, Gompertz, and Richards) and designing future demand based on IEA’s scenarios, the projections of future supply and demand trends of neodymium was obtained. This paper shows that though neodymium-based wind turbine construction might not be the cause for neodymium shortage, it would be confronted with material constraints in the future. Thus, more consideration should be taken in the investment of wind turbines with permanent magnet. Also, a mineral strategy, which integrates technological innovation, joint effort from different stakeholders, and better resource management, is required for a sustainable production of neodymium in the long run.

Power systems are critical infrastructures for the society. They are therefore planned and operated to provide a reliable eletricity delivery. The set of tools and methods to do so are gathered under security management and are designed to ensure that all operating constraints are fulfilled at all times. During the past decade, raising awareness about issues such as climate change, depletion of fossil fuels and energy security has triggered large investments in wind power. The limited predictability of wind power, in the form of forecast errors, pose a number of challenges for integrating wind power in power systems. This limited predictability increases the uncertainty already existing in power systems in the form of random occurrences of contingencies and load forecast errors. It is widely acknowledged that this added uncertainty due to wind power and other variable renewable energy sources will require new tools for security management as the penetration levels of these energy sources become significant. In this thesis, a set of tools for security management under uncertainty is developed. The key novelty in the proposed tools is that they build upon probabilistic descriptions, in terms of distribution functions, of the uncertainty. By considering the distribution functions of the uncertainty, the proposed tools can consider all possible future operating conditions captured in the probabilistic forecasts, as well as the likeliness of these operating conditions. By contrast, today's tools are based on the deterministic N-1 criterion that only considers one future operating condition and disregards its likelihood. Given a list of contingencies selected by the system operator and probabilitistic forecasts for the load and wind power, an operating risk is defined in this thesis as the sum of the probabilities of the pre- and post-contingency violations of the operating constraints, weighted by the probability of occurrence of the contingencies. For security assessment, this thesis proposes efficient Monte-Carlo methods to estimate the operating risk. Importance sampling is used to substantially reduce the computational time. In addition, sample-free analytical approximations are developed to quickly estimate the operating risk. For security enhancement, the analytical approximations are further embedded in an optimization problem that aims at obtaining the cheapest generation re-dispatch that ensures that the operating risk remains below a certain threshold. The proposed tools build upon approximations, developed in this thesis, of the stable feasible domain where all operating constraints are fulfilled. / <p>QC 20150508</p>

Wind power is often presented as a technique for energy production with many environmental benefits, especially since it does not emit any carbon dioxide. Most people are generally positive towards wind power. But when a wind farm is to be implemented on a local level, often resistance occurs. This study investigates how and why local perceptions of a wind farm differ. A qualitative method using interviews was chosen, and the focus has been on an area where a wind farm was planned. The results reveal that advocates have a users’ perspective on nature, while opponents have a conservation perspective. Advocates believe wind power can contribute to a better environment, while opponents believe that preserving natural areas is the best for the environment. Moreover, living in a calm landscape is part of the opponents’ identity, while the identities of the advocates, who often are active farmers, are connected to their ability to live from the land. Thirdly, whether a person recognizes the need for a change towards a renewable energy system or not also matters for the attitude. According to previous research, a person’s relationship to the landscape is of crucial importance for her/his attitude towards wind power implementation, and this is confirmed in the current study. Research also stresses that the visual impact of wind turbines is usually what creates most resistance, but this is not supported. The roles of information and citizen participation, which previous research found significant, are not confirmed as important either: Both were deficient, but this study cannot determine whether a better managed planning process would have made some of the interviewees more positive to it or not. Definitely, the claims from earlier research that Not-In-My-Back-Yard (NIMBY) motives are rarely the reason for resistance are supported.

Determining which countries are the most financially attractive for businesses to build wind projects is a matter of serious discussion that lacks succinct commentary. To fill this void this paper employs an empirical study of the wind subsidy support systems used by Germany, France, Spain and Sweden. This paper is based on the premise that businesses prefer to build where they can find the highest overall remuneration for their production; recognizing also the need for stability in those payments and businesses’ strong preference for larger early returns on their investments. The paper also analyzes the results and gives recommendations on possible improvements to each country’s system and where businesses should invest.In order to reach their 20-20-20 E.U. goals (European Commission, 2010), countries are encouraging the creation of new green energy projects, and this encouragement is frequently in the form of subsidies. The subsidy types used by the countries reviewed are feed-in tariffs, premiums and a certificate quota system. Each country’s support history is detailed along with the criteria of their respective systems.The countries systems are then compared using actual income and production data for four criteria at three different production levels – 100 percent, 75 percent and 150 percent of actual – and at two different lengths of time, 7 and 20 years. The first criteria of the comparison is total income, the second for variability of payments, the third for timing of payments and the final is the stability of the system itself.The results of this research show that the German and French systems are superior at all levels for their low variability in payment prices and in making larger payments to businesses earlier. They are also generally superior at lower and actual production levels for total income amounts. However, the Spanish options are superior at high levels of production for income and have middling variability levels. The Swedish system generally has the highest levels of variability for the lowest levels of income. Only the Spanish system is considered to be unstable in its political support of subsidies. Based upon the preceding findings are given to each country to improve their relative weaknesses. Also recommendations are given to businesses based upon the quality of the locations wind resources.

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Expectations for turbine-mounted lidar are increasing. The installation of lidars in wind turbine nacelles for measuring incoming winds, preventing wind gusts and increasing energy productions is after recently studies, technically and economically feasible. Among available lidar types, the most studied were continuous wave lidars because they were the most reliable apparatus when this initiative began. However, after studying technical considerations and checking commercial lidars, it was found that pulsed lidarslead this technology due to their promising results. The purpose of this report is to fill the gap between the interest in this technology and the absence of any academic papers that analyzes continuous-wave and pulsed lidars forthe mounted lidar concept. Hence, this report discusses the importance of turbine mounted lidars for wind power industry, different possible configurations and explains why specifically pulsed lidars are becoming more important for the mounted lidarmarket.

The aim of this thesis study is to design a hybrid energy system comprised of wind turbines, diesel generators and batteries to provide electricity for an off - grid rural community in Kenya. Wind Measurements collected over six years from 12 locations in Kenya have been studied and one site selected for this project due to its wind potential, geographical location and socio-economic potential. The energy system is designed to cater for the electricity demand of 500 households, one school, one medical clinic and an irrigation system. The system will support up to 3000 people. The Hybrid Optimization Model for Electric Renewables (HOMER) is the software tool that has been used to simulate the hybrid system and analyze its results. The optimization has been carried out and presented according to cost of electricity and sensitivity graphs have been used demonstrate the optimization based on diesel price and wind turbine hub height.

Planning electricity supply is important because power demand continues to increase while there is a concomitant desire to increase reliance on renewable sources. Extant, research pays particular attention to highly variable, low-carbon energy sources such as wind and small-scale hydroelectric power. Models generally employ only a simple load leveling technique, ensuring that generation meets demand in every period. The current research considers the power transmission system as well as load leveling. A network model is developed to simulate the integration of highly variable non-dispatchable power into an electrical grid that relies on traditional generation sources, while remaining within the network's operating constraints. The model minimizes a quadratic cost function over two periods of 336 hours, with periods representing low (summer) and high (winter) demand, subject to various linear constraints. The model is numerically solved using Matlab and GAMS software environments. Results indicate that the economic benefit of introducing zero cost wind into an existing system heavily depends on the existing generation mixture, with system cost reductions favoring wind penetration into thermally dominated mixtures. Results also show that integrating wind power into a generation mixture with a large percentage of coal capacity can increase emissions for moderate wind penetrations, and that coal facilities may economically replace lower cost alternatives under certain conditions.

Wind energy conversion is the fastest-growing source of renewable electric power generation in the world and it is expected to remain so for some time. Doubly Fed Induction Generators (DFIGs) hold more than 50% market share of wind power generators due to its unique benefits of low cost, control capability and scalability. Recent trend of DFIGs installed in wind power are within power range of 200KW-2MW and have stator windings rated at 690V, which are highly susceptible to inter-turn faults. This fault type account for more than 40% of the total failure causes of the generator. A reliable fault diagnostic system to detect this fault at incipient stage is highly in demand to prevent catastrophic failures and reduce preventive maintenance costs, since regular inspection is expensive and rewinding of generator takes time in period of days and costs nearly 20% of the original generator cost. Conventional techniques developed for detecting stator inter-turn faults in induction motor are not directly applicable for this machine partly due to difference in construction and their operating characteristics. Research for fault diagnosis in last 5 years has lead to variety of techniques, but none have proved to be feasible either due to need for dedicated sensors and high computing needs or they fail to account for operating conditions which lead to ambiguous fault triggering. This absence of any proven technique to detect stator inter-turn faults in DFIG and the dire necessity for a fault diagnostic system to promote their reliability in wind power generation has motivated the research of this thesis. A novel technique to detect stator inter-turn faults in a DFIG is proposed by analyzing rotor current and search coil voltage in this thesis. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator inter-turn faults in DFIGs. Hence. in this study, an in-depth investigation was conducted to determine the origin of various harmonic components in the rotor currents and their feasibility to detect inter-turn stator faults unambiguously. The theory is verified by modeling the DFIG and simulating various operating conditions of healthy state. severity of faults and unbalance loading conditions that cause ambiguity. Further to verify the concept, an experimental test-bed was created and tests were carried out on DFIG under varying speed operations, fault severity and loading conditions. The experimental results achieved from analyzing the frequency spectrum of rotor current and search coil voltage have been compared and discussed. To verify feasibility of the proposed technique for detecting stator inter-turn faults and obtain results on speed sensitivity of fault detection, a prototype of DSP based Fault Diagnostic device was developed. Further discussion is made on challenges of realizing the proposed fault diagnostic technique in the industry and scope for further improvement.