abstract: With the increasing penetration of converter interfaced renewable generation into power systems, the structure and behavior of the power system is changing, catalyzing alterations and enhancements in modeling and simulation methods. This work puts forth a Hybrid Electromagnetic Transient-Transient Stability simulation method implemented using MATLAB and Simulink, to study power electronic based power systems. Hybrid Simulation enables detailed, accurate modeling, along with fast, efficient simulation, on account of the Electromagnetic Transient (EMT) and Transient Stability (TS) simulations respectively. A critical component of hybrid simulation is the interaction between the EMT and TS simulators, established through a well-defined interface technique, which has been explored in detail. This research focuses on the boundary conditions and interaction between the two simulation models for optimum accuracy and computational efficiency. A case study has been carried out employing the proposed hybrid simulation method. The test case used is the IEEE 9-bus system, modified to integrate it with a solar PV plant. The validation of the hybrid model with the benchmark full EMT model, along with the analysis of the accuracy and efficiency, has been performed. The steady-state and transient analysis results demonstrate that the performance of the hybrid simulation method is competent. The hybrid simulation technique suitably captures accuracy of EMT simulation and efficiency of TS simulation, therefore adequately representing the behavior of power systems with high penetration of converter interfaced generation. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2018

Thesis (Master of Engineering in Electrical Engineering)--Cape Peninsula University of Technology, 2018. / In Sub-Saharan Africa (SSA), there are several challenges that hinder development. One of these challenges is access to electricity. There are numerous benefits to having access to reliable electricity. These include less time spent fetching water from rivers and dams, as water purification systems for households could be used in villages; children in villages would be able to spend more time doing their schoolwork and not fetching wood for fire; and automated irrigation systems could be used for villagers to farm and make an income. Finding alternative ways to generate electricity would enable access to electricity for regions that currently do not have the electricity. This means that large organisations need to find alternative ways of generating electricity, as they have the means to do so. With the current renewable energy technologies available, there are now more ways in which electricity could be generated. The use of biomass is no exception to this. With constant developments in the renewable energy sector, waste-to-energy (WtE) is proving to be a viable method to generate electricity. The main aim of this research was to determine if a commercial food retailing organisation could use their food waste for generating electricity for their own use to reduce their demand from the central grid. A way of determining the viability of this type of technology is using a software that simulates renewable energy projects. In this research, an organisation was contacted for waste data. Systems for two of the stores will be simulated and results will be discussed. The organisation will remain anonymous. The software used in this research is System Advisor Model (SAM), which was developed by the National Renewable Energy Laboratory (NREL) in the United States. In the results, three results were discussed. These are the monthly energy, monthly heat rate and the monthly boiler efficiency for each of the stores for Store 1, the annual energy simulated was 138,509 kWh and 131,677 kWh for Store 2. Monthly energy averages for each store were 11,542 kWh for Store 1 and 10,973 kWh for Store 2, respectively. There are several opportunities for research based on the findings. These include researching other food sectors in the study; conducting a financial analysis of small-scale WtE systems; constructing a prototype of the system; and using three different softwares to simulate a system for the same project.

Esta dissertação visa estimar o potencial de energia elétrica do biogás, conhecido também como gás de aterro, gerado por resíduos sólidos urbanos (RSU) no Brasil. A estimativa foi aplicada para todos os 5.565 municípios do Brasil. O método utilizado para estimar a geração de biogás foi o IPCC 2000 (First Order Decay - FOD), pois leva em consideração inúmeros parâmetros, como a composição da matéria orgânica no aterro, teor de umidade do lixo, grau de compactação, temperatura no interior do aterro. Adicionalmente, este método é o mais difundido mundialmente e é o mesmo método utilizado para inventários de Gases de Efeito Estufa no Brasil, permitindo, dessa forma, comparações entre os estudos. No método, foram empregados os dados dos censos do IBGE 1970, 1980, 1991, 2000, 2010 de forma a representar fielmente o crescimento populacional e possibilita estimar a quantidade de resíduos sólidos gerados para todos os anos estudados. No estudo, foram analisados três cenários distintos representando diferentes tendências na gestão de resíduos no Brasil (cenários de referência, otimista e pessimista). O potencial elétrico do biogás no Brasil de acordo com o Cenário de referência para 2013 é de 983 MW, representando 1,6 % da potência elétrica instalada atual e para o ano de 2020, o potencial é de 1.602 MW. Concluindo o estudo, foram realizadas análises financeira e de sensibilidade em três diferentes projetos para avaliação da viabilidade de cada projeto. / This dissertation aims to estimate the potential for energy recovery from landfill gas through municipal solid waste (MSW) in Brazil. The survey was carried out in all 5,565 municipalities in Brazil. The used method to estimate the generation of landfill gas was the IPCC 2000 (First Order Decay - FOD) because it takes into account several parameters, such as: the type of organic matter, the waste moisture content, degree of compaction and temperature inside the landfill. Additionally, this method is the most widespread in the world and it is the same method used in greenhouse gases inventories in Brazil, thus allowing comparisons between these studies. In the method, data from national census of 1970, 1980, 1991, 2000, 2010 was used in order to accurately represent the population growth and allows estimating the amount of solid waste generated in every year. The study analyzed three different scenarios representing different trends in the solid waste management in Brazil (reference, optimistic and pessimistic scenarios). The electrical potential of landfill gas in Brazil (in the reference scenario) in 2013 is 983 MW, representing 1.6% of the current installed capacity and for 2020, the electrical potential is 1,602 MW. Concluding this study, a financial and sensitivity analysis as carried out on three different projects to evaluate the feasibility of each project.

O presente estudo teve como principal objetivo avaliar a produção de hidrogênio a partir de diferentes concentrações de vinhaça de cana-de-açúcar a 370°C e 55°C. Além disso, os consórcios microbianos mesófilo e termófilo utilizados nos ensaios em reatores em batelada foram caracterizados por meio da técnica de clonagem e sequenciamento do gene RNAr 16S visando conhecer a diversidade de bactérias. Os ensaios de produção de hidrogênio foram realizados após o enriquecimento dos consócios microbianos a partir de lodo de reator UASB em condição mesófila e termófila utilizando vinhaça como fonte de carbono. Todos os ensaios foram realizados em triplicata de reatores em batelada com aproximadamente 2, 5, 7 e 12 g DQO/L de vinhaça, sendo monitorada a produção de hidrogênio, ácidos orgânicos e solventes, além de carboidratos totais solúveis. O potencial de produção de hidrogênio foi maior para concentrações crescentes de vinhaça; ou seja, de 4,3 para 28,4 mmol \'H IND.2\' nos ensaios a 37°C. Para os ensaios termófilos esses valores foram bastante similares entre si, variando de 5 a 6,7 mmol \'H IND.2\'. Em relação ao rendimento de produção de \'H IND.2\', observou-se que não ocorreu variação com aumento da concentração de substrato para os ensaios mesófilos (10 mmol \'H IND.2\'/g carboidratos totais), todavia, para os ensaios termófilos o rendimento diminuiu com o aumento da concentração de vinhaça, ou seja, de 21,7 (2 g DQO/L) para 3,2 mmol \'H IND.2\'/g carboidratos totais (12 g DQO/L). Nos ensaios mesófilos, obteve-se degradação acima de 79% do substrato orgânico, enquanto para os ensaios termófilos esse valor variou de 36 a 6 %. Os metabólitos gerados foram ácido acético e butírico nos ensaios mesófilos e, somente ácido butírico nos ensaios termófilos. Clones provenientes do consórcio mesófilo foram similares a microrganismos das famílias Clostridiaceae (75%) e Ruminococcaceae (22%). Em contrapartida, no consórcio termófilo, 96% dos clones foram filogeneticamente relacionados a Thermoanaerobacterium. As cepas microbianas isoladas (CA e C1) apresentaram rendimento de produção de hidrogênio de 10 e 1,1 mmol \'H IND.2\'/g glicose, respectivamente. CA e C1 foram similares (100%) a Clostridium acetobutylicum e Clostridium carboxidivorans. / The present study aimed to evaluate the production of hydrogen from different concentrations of sugar cane vinasse at 37°C and 55°C. Moreover, the mesophilic and thermophilic microbial consortia used in the hydrogen production tests were characterized by cloning and sequencing techniques to know its microbial diversity. Hydrogen production tests were carried out after the microbial enrichment from a UASB granular sludge at a temperature of 37°C and 55°C using vinasse as sole carbon source. All assays were performed in triplicate of batch reactors with about 2, 5, 7 and 12 g COD/L of vinasse. During the assays \'H IND.2\', solvents and organic acids production as well as the soluble carbohydrates were measured. Potentials of hydrogen production increased with the increasing concentration of substrate in the mesophilic tests (4.3 to 28.4 mmol \'H IND.2\'). However, for the thermophilic tests, the hydrogen production potentials were very similar among them, ranging from 5 to 6.7 mmol \'H IND.2\'. For the mesophilic tests, the hydrogen yields did not change with increasing the vinasse concentration for the (values around 10 mmol \'H IND.2\'/g carbohydrates), however, for the thermophilic tests the hydrogen yields decreased with the increase of vinasse concentration, the yield ranged from 21.7 (2 g COD/L) to 3.2 mmol \'H IND.2\'/g carbohydrate (12 g COD/L). The efficiency of substrate degradation was higher for mesophilic tests, and its minor value was 79%. For the thermophilic tests, the substrate consumption was lower, and the values ranged from 36 to 61%. The metabolites generated were acetic and butyric acids for tests at 37°C and butyric acids for the tests at 55°C. The mesophilic clones were similar to the family Clostridiaceae (75%) and Ruminococcaceae (22%). In contrast, the thermophilic consortium presented 96% of clones related to Thermoanaerobacterium. Isolated bacterial strains (CA and C1) showed hydrogen yields of 10 and 1.1 mmol \'H IND.2\'/g glucose, respectively. CA and C1 were similar to Clostridium acetobutylicum (100%) and Clostridium carboxidivorans (100%).

O objetivo deste estudo foi estimar os efeitos da curva de aprendizado sobre a competitividade de fontes energéticas, tais como petróleo, carvão, gás natural, biomassa (etanol), hidroeletricidade, nuclear, eólica e fotovoltaica, e propor medidas regulatórias que incentivem as tecnologias renováveis. Para tanto, se propôs a utilização da abordagem de learning curves, que considera três efeitos principais para explicar a redução dos custos de produção: o efeito especialização (chamado de learning by doing), o efeito escala (scale effect) e o efeito da pesquisa e desenvolvimento - P&D (learning by searching). Identificou-se o peso desses efeitos por fonte energética com vistas a auxiliar no direcionamento de incentivos às energias renováveis, de modo a se decidir se a ênfase deve ser dada à especialização, escala ou P&D. Embora os modelos originais de learning curves tenham sido idealizados a partir da trajetória dos custos, devido a facilidades operacionais a literatura na área vem adotando o preço como proxy de custos. Neste estudo, a orientação do modelo a custos ou a preços foi objeto de uma avaliação através de análise concorrencial. Como resultado, verificou-se que a adoção de preços como proxy de custos mostrou-se possível para a maioria das fontes analisadas devido a um grau satisfatório de concorrência dos mercados relativos a essas fontes de energia. Uma vez definida a orientação do modelo, a metodologia proposta envolveu estimar os três efeitos por métodos econométricos. Os resultados indicaram que as fontes carvão, petróleo e gás, energia nuclear e fotovoltaica reagiram ao efeito aprendizado, embora não apresentassem resposta expressiva quanto aos gastos em P&D. Já as fontes eólica e etanol mostraram-se sensíveis aos gastos em P&D e ao efeito escala, sendo a escala também determinante dos preços da energia nuclear e hidroeletricidade. Esses resultados auxiliaram na proposição de medidas públicas específicas como estímulo às fontes renováveis. / The goal of this study is to estimate the effects of the learning process on the competitiveness of the main energy sources, such as oil, coal, natural gas, biomass (ethanol), hydroelectricity, nuclear energy, wind power, and photovoltaic energy, and propose regulatory measures to encourage renewable technologies. The learning curves approach adopted in this thesis considers three main effects to explain the reduction in production costs: the learning by doing effect, the scale effect and the learning by searching effect. The relevance of these three effects was identified for energy source, in order to assist in the incentives direction to promote renewable energy. Although the original models of learning curves approach have been conceived from the point of view of the costs, in the related literature the price has been adopted as a proxy due to operational facilities. In this study, the model orientation to costs or prices was chosen using a competitive analysis. It was found that price orientation could be applied to most sources, since there is enough competition in the markets. Once defined model orientation, the proposed methodology involves estimations of the three effects by econometric methods. The results showed that coal, oil and gas, nuclear and photovoltaic energy react to learning effect, though searching effect is not so important. Wind and ethanol are sensitive to searching and scale effects. Scale effects also determine the nuclear power and hydroelectricity prices. From these results, specific public measures are proposed for each renewable source.

The solar energy, or photovoltaic (PV) industry, driven by economic competition with traditional fossil energy sources, strives to produce solar panels of the highest conversion efficiency and best reliability at the lowest production cost. Solar cells based on crystalline silicon are currently the dominant commercial PV technology by a large margin, and they are likely to remain dominant for at least one decade. The problem of improvement mechanical stability of silicon wafers and finished solar cell is one of the most critical for entire PV industry. Mechanical defects in wafer and cells in the form of periphery or internal cracks can be initiated at various steps of the manufacturing process and becomes the trigger for the fracture. There are a limited number of characterization methods for crack detection but only a few of those are able to satisfy PV industry needs in sensitivity of the crack detection incorporated with the analysis time. The most promising are a Resonance Ultrasonic Vibrations (RUV) technique and Photoluminescence (PL) imaging. The RUV method was further developed in this thesis project for fast non-destructive crack detection in full-size silicon wafers and solar cells. The RUV methodology relies on deviations of the resonance frequency response curve measured on a wafer with peripheral or bulk millimeter-length crack when it is compared with identical non-cracked wafers. It was observed that statistical variations of the RUV parameters on a similarly processed silicon wafers/cells with the same geometry lead to false positive events reducing accuracy of the RUV method. A new statistical approach using three independent RUV crack detection criteria was developed and applied to resolve this issue. This approach was validated experimentally. Crack detection using RUV technique was applied to a set of production-grade Cz-Si wafers and finished solar cells from the Isofoton's S.A. (Spain) production line. Cracked solar cells rejected by the RUV method using the statistical approach were imaged with room temperature PL mapping and independently controlled with Scanning Acoustic Microscopy (SAM). A comparison of three independent techniques for crack detection, RUV, PL and SAM, was performed on selected samples. A high accuracy and selectivity of the RUV method to identify mm-size cracks in wafers and cells was confirmed.

Providing energy security and diversifying the energy production in India align with the country’s rising power ambitions and policy goals to industrialize. Renewable energy provides a useful tool for the state to meet these policy goals without producing more air pollution and additional environmental degradation. The Central Government has international ambitions of with becoming a rising responsible power; these aspirations have created new resources, incentives, and policy ideas for the subnational states in India. The purpose of this thesis is to map out the motivations, interests, and incentives of subnational elites in devising policies to promote renewable energy development in Tamil Nadu, Kerala, Gujarat, and Rajasthan. I develop an analytical framework based on four variables: 1) state-level party politics, 2) financial space/ indebtedness of state distribution companies, 3) institutional knowledge in state-level nodal renewable energy agencies, and 4) state-level linkages with the private sector to examine different modes of vertical alignment that subnational actors employ to develop renewable energy policies. I find that environmental concerns weren’t the primary driver of renewable energy development; instead, environmental benefits were an unintended outcome of private sector actors and state elites coordinating with the Central Government to address the pressing needs of ensuring reliable energy for industry leaders. In particular, Kerala demonstrates that even when active environmental movements and popular support exists for renewable energy, unless there are active private sector linkages, renewable energy development will remain slow. These findings may be very helpful for central government officials in India and state-level bureaucrats trying to devise climate change mitigation policies on the subnational level. Moreover, international climate change negotiators could use these findings to engage with India more to accelerate renewable energy development to slow anthropogenic climate change.

As the international community takes increasing action to mitigate the effects of climate change, increased focus has been placed on the topic of energy transitions in developing countries. This paper uses the multi-level perspective (MLP) framework to analyze the ongoing energy transition in Mongolia, specifically the integration of large-scale wind and solar energy systems. Attention is paid to the presence of transnational linkages and intermediaries that have substantially contributed to Mongolia’s success in diffusing renewable energy technology, as well as challenges Mongolia has faced as a result of limited technological and institutional capacity. The paper concludes that Mongolia’s transition shares many similarities with other developing countries’ transitions, in that transition dynamics are highly influenced by exogenous actors and interests, rather than traditional factors as described by the MLP.

This licentiate thesis presents a new way of understanding Electric Power. The new perspective on Electric Power highlights the similarities between our banking system and our power system. The two different systems share a common abstraction. In the case of the banking system this abstraction is fully accepted. In the case of the power system this abstraction is not yet fully accepted. This thesis aims to clarify this abstraction and show the parallelism between the two systems and the two abstractions. This thesis examines what the Product Electricity really is. What is it, in reality, we sign a power contract to buy and pay for, and how is this product transferred to us? This new understanding challenges the old, physical understanding of Electric Power. Understanding the similarity between our banking system and our power system becomes important when we examine our Power Markets, and it becomes absolutely vital to understand for those investing in new power generation. In no way does this new understanding of Electric Power question or challenge the physics behind power generation and power transfer. Maxwell’s equations holds true. The laws of Ohm and Kirchhoff are still the laws by which the electrical and power system engineers must abide. But when it comes to the Product Electricity, the product traded on our Power Markets, the product that we sign power contracts to buy and pay for, there is a major difference. The new understanding challenges the old quite dramatically. It does in fact show that the old, physical perspective on the Product Electricity is flawed and has been a misconception for over a century. My primary goal in this thesis is to thoroughly explain the new perspective and by so doing clarify and dissolve the old misconception of what the Product Electricity actually is. The scientific theory of the Greenhouse Effect now has over 195 years of published peer-reviewed science.[[i]] The threat of accelerating Climate Change is a scientifically solid fact. The Paris agreement must be met. My second goal with this thesis is to make credible that an electrification of our society is a possible and viable option. The possibility of a swift energy transition from fossil fuels to renewable electricity is made more likely, and more viable, thanks to the new understanding of what Electric Power really is, because now we have the de facto choice of not consuming any fossil power. © Per Ribbing, April 2019 [i] Joseph Fourier, Remarques générales sur les températures du globe terrestre et des espaces planétaires”, Annales de Chimie et de Physique, 27, 1824, p. 136-167

The objective of this thesis is to provide a foundation for evaluating the water costs associated with electricity production to calculate the avoided water cost of energy for solar PV and wind technologies relative to coal, natural gas, nuclear, geothermal, concentrated solar thermal, and biomass. Water consumption is estimated for energy production (fuel extraction and preparation) and electricity generation (power plant operation) using the best available information from published articles. The quantity of water consumed for electricity production is monetized for a Southern California case study based on the water rates of Metropolitan Water District of Southern California (MET), which is the largest wholesale supplier of surface water in the United States. Water withdrawals are addressed but not included in the monetization of water consumption. Case studies of specific power plant’s water costs are used for comparison and demonstrate variation in water costs due to variations in water consumption. Water costs are estimated in terms of water cost ($) per unit energy generated (MWh). Since solar PV and wind energy are shown to have negligible water consumption relative to the other technologies, the water costs for each of the other electrical generation methods are equivalent to the water savings potential of solar PV and wind generated electricity. Compared to other evaluated electricity sources that could provide electricity to Southern California, solar PV and wind energy can save water worth $0.76/MWh for natural gas combined-cycle plants, $0.94/MWh for geothermal power plants, $1.01/MWh for biomass power plants, between $1.14 and $1.82 per MWh for concentrated solar thermal plants, $1.43/MWh for nuclear power plants, and $1.49/MWh for coal power plants. Results indicate that there are three processes that use substantial amounts of water: fuel extraction (for coal, natural gas, and nuclear), thermoelectric cooling of power plants and emissions controls such as carbon capture and sequestration. Carbon capture and sequestration are estimated to almost double the water consumption costs of coal and natural gas power plants. Of the evaluated technologies, only solar PV and wind do not require any of those three steps. Solar PV and wind energy can thus save the greatest value of water when displacing power plants that utilize (or may someday be required to utilize) all three of the major culprits of water consumption. Even the use of one of these processes (particularly thermoelectric cooling) results in substantial water consumption. Total water costs for each technology were normalized to the total expected electrical output of a typical capacity natural gas combined-cycle power plant to demonstrate the economies of scale of power production. Over a forty year lifespan of a typical natural gas power plant, total water consumption would result in $67 million worth of water (southern CA wholesale prices). To generate the same amount of electricity the total value of water consumption is estimated to be $83 million for geothermal plants, $89 million for biomass plants, $100 million to $160 million for concentrated solar thermal plants, $126 million for nuclear plants, and $131 million for coal power plants. The use of carbon capture and sequestration is expected to nearly double these total water costs. Compliance with environmental regulations can cause expenses much greater than water consumption. For example, mitigation costs for impingement and entrainment (a consequence of cooling water withdrawals) as well as the cost to convert to closed-loop cooling for environmental compliance can be considered costs associated with water usage. This is demonstrated by a case study about the Los Angeles Department of Water and Power regarding the elimination of once through cooling. The conversion to closed-loop cooling for the Haynes natural gas power plant is expected to cost $782 million, resulting in an estimated unit cost of $10.66/MWh. Finally, the economic benefits of the California Renewables Portfolio Standard are calculated with respect to water consumption. By holding hydroelectricity, geothermal, biomass and CST production constant and utilizing solar PV and wind to meet the 33% renewables target by 2020, a water value of $28.5 million/year can be conserved relative to meeting rising electricity demand with only natural gas combined-cycle generation. MET water rates increased 70% from 2008 to 2014. If water rates increase at the same rate over the next six years, the water savings of the Renewable Portfolio Standard would be 70% higher in 2020 dollars, equating to water savings of $48.4 million per year.