<p>  The interfacial reactions of the electrolytes at the electrode-electrolyte interface determine critical properties of the battery chemistries including the reaction reversibility, kinetic, and thermal stability etc. Rationally designing the solvation structure of the liquid electrolytes is paramount in altering their interfacial behaviors and achieving desirable battery performance. This thesis aims to provide fundamental understandings to the electrolyte solvation structure design in its correlations to the battery interphase stability and formation mechanism, interfacial desolvation kinetic, and thermal stability, providing strategies to build next-generation secondary batteries with improved energy density, wide-temperature capability, and thermal safety. </p> <p>Developing high-voltage lithium metal battery (LMB) with metallic Li anode and nickel-rich metal oxide cathode is a feasible approach to enhance the battery energy density. However, inferior interfacial stabilities of conventional electrolytes towards highly reductive anode and oxidative cathode cause severe parasitic reactions. This thesis investigates the solvation structures of ether-based electrolytes and their interfacial decomposition pathways to selectively control the solid electrolyte interphase (SEI) composition. Combined theoretical and experimental studies demonstrate that lessening the coordination strength of the solvent molecules can improve the ion aggregating degrees in the solvation shell and preferentially promote the anion decomposition. Detailed surficial characterizations identify that weakly-solvating electrolytes generate robust SEIs with enriched inorganic components on anode and cathode surface, which kinetically prohibits parasitic reactions. The strategy successfully facilitates the long-term cycling of high energy LMBs. Weakening the solvent coordination ability is also identified effective to promote the desolvation kinetic and realize high battery energy retention at low temperatures.</p> <p>The approach of tailoring ion-pairing behavior to achieve stabilized electrode-electrolyte interface is further validated in multivalent battery systems such as Magnesium-ion batteries (MIBs). Multivalent cations like Mg2+ and Zn2+ possess high electron density which results in strong coordination to solvent molecules and hindered desolvation process. They usually induce large reaction overpotential and low efficiency. The methoxy-amine-based electrolytes for MIBs are selected in terms of elucidating their interfacial failure mechanism and the solvation structure-dependent reaction stabilities with Mg metal anode. The study reveals an unknown amine solvent dehydrogenation mechanism that compromises the Mg anode stability. The tight coordination between solvent amine group (-NH2) and cation causes its direct reduction with H2 release. The dehydrogenation products tend to diffuse into the liquid electrolyte phase, which promotes the interfacial electrolyte decay. This work also demonstrates the approach to strengthen the solvent molecule stabilities via restructuring the Mg2+ solvation shell. Introducing anion coordination to Mg2+ can effectively relief the amine-cation interaction and suppress its reduction. As the result, hundreds of stable cycling from Mg metal anode with more than 99.6 % efficiency is achieved.</p> <p>Finally, the thermal stability of electrolytes featuring various solvation structures are studied in LMBs via quantitative thermal analysis and surficial characterization techniques. The thermal runaway of batteries which is known to be initiated via SEI decomposition and propagated by exothermic electrode-electrolyte reactions exhibit great dependence on the solvation structures of the liquid electrolytes. The results suggest that strong solvent-coordinating electrolytes with solvent-separated ion pair structures are prone to exothermic reduction decompositions. While the organic-rich SEI tends to decompose at low temperatures and initiate thermal runaway easily. Therefore, designing electrolytes with anion involved solvation shells that generate inorganic SEI can effectively mitigate the thermal runaway behavior. Supplementary research focusing on the thermal safety of Potassium-ion battery also indicates the critical role of SEI stability on the overall battery safety aspect, which is governed by the electrolyte composition.</p>

<p dir="ltr">Deciding setpoints for distributed energy resources (DERs) via local control rules rather than centralized optimization offers significant autonomy. The IEEE Standard 1547 recommends deciding DER setpoints using Volt/VAR rules. Although such rules are specified as non-increasing piecewise-affine, their exact shape is left for the utility operators to decide and possibly customize per bus and grid conditions. To address this need, this thesis optimally designs Volt/VAR rules to minimize ohmic losses on lines while maintaining voltages within allowable limits. This is practically relevant as excessive reactive injections could reduce equipment's lifetime due to overloading. First, we consider a linearized single-phase grid model. Even under this setting, optimal rule design (ORD) is technically challenging as Volt/VAR rules entail mixed-integer models, stability implications, and uncertainties in grid loading. Uncertainty is handled by minimizing the average losses under voltage chance constraints. To cope with the piecewise-affine shape of the rules, we build upon our previous reformulation of ORD as a deep learning task. A recursive neural network (RNN) surrogates Volt/VAR dynamics and thanks to back-propagation, we expedite this chance-constrained ORD. RNN weights coincide with rule parameters, and are trained using primal-dual decomposition. Second, we consider a multi-phase grid model with alternating current power flow (AC-PF). Different from the single-phase model, we additionally add imbalance chance constraints and use chain rule differentiation to obtain derivatives during the primal-dual updates. Numerical tests corroborate the efficacy of this novel ORD formulation and solution methodology.</p>

Using chilled water within South African gold mines is paramount to the purpose of extracting gold ore efficiently. Using water for cooling, drilling and sweeping and the release of underground fissure water causes the accumulation of vast amounts of water in underground dams. Deep mines use cascading pump systems for dewatering, which is an electrical energy intensive dewatering method. Due to the recent equalisation of demand to generation capacity of electrical energy in South Africa, various methods towards demand side reduction have been implemented. With the introduction of a time-of-use (TOU) tariff structure by Eskom, the implementation of projects that shift load from peak TOU times to times of the day when electrical energy is less expensive has increased. To enable load shifting on mine dewatering pumps, preparation before and recovery after peak TOU is needed for effective results. This induces a preparation- and comeback load in the standard TOU. With an annual increase in TOU tariffs and the rate of increase of standard TOU being greater than that of the peak TOU, a reduction in electrical energy consumption before and after peak TOU is needed. To enable this, a step-by-step control technique was developed to promote the shifting of load from standard- to off-peak TOU, while still realising a full load shift from peak TOU. This technique entails dynamic control ranges of underground dam levels as opposed to the conventional constant control range method. Two case studies were used to test the developed technique. Results indicated significant additional financial savings when compared to conventional control methods. Additional savings of R1,096,056.65 and R579,394.27 per annum were respectively achieved for both case studies. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Thesis. (M. Tech. (Dept. Electronic Engineering, Faculty of Engineering and Technology))--Vaal University of Technology, 2011. / There are a number of ways to produce hydrogen using solar energy as the primary source. Water electrolysis, which uses solar electrical energy, is the rapidly available process. Hydrogen can be produced by using solar electric energy from photovoltaic (PV) modules for the electrolysis of water without emitting carbon dioxide or requiring fossil fuels. Solar hydrogen energy systems are considered one of the cleanest hydrogen production technologies, where the hydrogen is obtained from sunlight by directly connecting the photovoltaic modules to the hydrogen generator. This dissertation presents a designed solar photovoltaic electrolyser hydrogen production and storage system for various applications such as in the power generation and telecommunications industries. Various experiments were performed on the designed system to ensure its reliability and conformity with theoretical findings. The purity of the generated hydrogen was determined. The relationship between the amount of solar irradiance reaching the surface of the PV panel, the PV panel surface temperature, the PV panel tilt angle and the maximum power point voltage and current of the PV panel array were also considered. The effect of dust on the panel voltage and current outputs was also determined. Finally, the factors to consider when designing a solar photovoltaic electrolyser hydrogen system (based on this study) were enumerated.

Este trabalho apresenta uma metodologia para a determinação do potencial de conservação de energia elétrica de usos finais, orientada para a análise de instalações de ensino, aplicável, também, a instalações comerciais em geral. Os usos finais considerados no trabalho são: iluminação, ar condicionado, microcomputadores pessoais e outros equipamentos elétricos. São apresentados procedimentos para o levantamento de dados e para a determinação do potencial de conservação de energia elétrica de cada uso final analisado, além de uma metodologia estatística para a análise de contas de energia elétrica. São definidos, também, indicadores do uso de energia elétrica bastante úteis em diagnósticos energéticos, permitindo estimar o potencial de conservação da instalação a partir da análise comparativa de seus índices com valores típicos obtidos em outros diagnósticos energéticos ou em publicações especializadas. A aplicação prática da metodologia é apresentada na forma de um estudo de caso, realizado em 1996 na Cidade Universitária Armando de Salles Oliveira - CUASO, o maior campus da Universidade de São Paulo – USP e um dos maiores do Brasil, localizado na cidade de São Paulo. Um volume considerável de informações é analisado e discutido em detalhes, fornecendo dados globais e desagregados em usos finais sobre as características de consumo e os potenciais de conservação de energia elétrica do campus. / This work presents a methodology for determining the potential of electric energy conservation of electricity end uses. The methodology is oriented to university premises, but it is also applicable to other types of installations. End uses considered in this work include lighting, air conditioning, personal computers and other electric devices. Procedures for data gathering and determination of conservation potential of each end use are presented. A statistical methodology for analyzing electricity bills is also presented. Furthermore, some useful indicators for energy diagnoses are developed. These indicators allow the estimation of the conservation potential of a given installation through comparison with typical values extracted from the other energy diagnoses or technical literature. The proposed methodology was applied in the main campus of University of São Paulo – USP, one of the largest in Brazil with some 30,000 undergraduate students. A large amount of data is analyzed and discussed, yielding global and specific indicators regarding end use characteristics and conservation potential within the campus.

Este trabalho tem como objetivo principal analisar o desenvolvimento da indústria da energia elétrica brasileira, a formação e composição das tarifas de energia elétrica e suas implicações e reflexos na economia em geral. Nesse sentido foi feito um breve histórico dessa indústria desde o ano de 1.993, que foi o ano em que se migrou de uma regulação de tarifas pelo sistema denominado custo do serviço para o sistema regulatório denominado price cap, ou seja, preços máximos pelo sistema de incentivos. Foi analisada essa linha regulatória que passou basicamente por dois governos sucessivos, com dois mandatos consecutivos. Fernando Henrique Cardoso no período de 1994 a 2003, que traçou as linhas mestras dessa regulação, com um programa de privatizações de empresas geradoras, transmissoras e distribuidoras de energia elétrica, delegando à iniciativa privada a maior parte da responsabilidade desse serviço. Nessa fase foram constituídas diversas agências reguladoras, sendo criada a ANEEL Agência Nacional de Energia Elétrica, com o objetivo de regular e mediar os interesses dos investidores e dos consumidores. Posteriormente, no governo Luis Inácio Lula da Silva, foi dada continuidade à esse tipo de regulação, com algumas modificações, basicamente na área do planejamento indicativo da expansão do sistema elétrico, que havia sido abandonado. Para analisar o comportamento das tarifas de energia elétrica desde o ano de 2005, foram eleitas cinco distribuidoras de energia elétrica representativas da diversidade geográfica brasileira, e comparado o crescimento do IGP-M com o crescimento das tarifas de consumidores típicos. / This dissertation has as main goal the analysis of the Brazilian electrical energy industry development, the formation and composition of electrical energy fees and its implication and reflexes in the economy as general. This way it is made a small historic of this industry since the year of 1993, which was the year that the regulation of fees by the system named custo do serviço migrated to the regulatory system named price cap, in other words, maximum prices by the system of incentives. This regulatory line, which basically went through two governments successively, was analyzed with two consecutive mandates, Fernando Henrique Cardoso during the period from 1994 to 2003, who wrote the main lines of this regulation, with a program of privatization of generation, transmission and distribution companies, delegating to the private initiative the major part of the responsibility of this service. In this phase were constituted many regulatory agencies, being also created the ANEEL - Agência Nacional de Energia Elétrica (Electrical Energy National Agency), with the goal to regulate and mediate the interests of the investors and consumers. Lately, during the government of Luiz Inácio Lula da Silva, it was given continuity to this kind regulation, with some modifications, basically in the area of planning indicating the expansion of the electrical system, which was abandoned. To analyze the behavior of the electrical energy fees since the year of 2005, were chosen five distributors of electrical energy representatives of the Brazilian geographical diversity and it was made the comparison between the growth of the IGP-M and the growth of the typical consumer fees.

O presente trabalho compreende o estudo de campanhas de comunicação de racionamento de água e luz elétrica pela ótica dos conceitos de dilema social e comunicação de riscos. Para tal, revisamos a bibliografia desses temas e elaboramos uma proposta de análise de conteúdo temática que busca identificar valores e normas sociais desses conceitos nas campanhas publicitárias de dois casos brasileiros escolhidos. / This dissertation involves the study of communication campaigns of water and electrical energy in rationing situations by using concepts of social dilemmas and risk communication. In order to achieve these results, we have reviewed the literature of these subjects, and we have proposed a model of content thematic analysis to identify values and norms of these two concepts on social campaigns of two Brazilian cases.

O aumento da população, o crescimento das grandes cidades, da industrialização e do consumo, tem trazido preocupação com relação a sustentabilidade quanto à disponibilidade energética e quanto à destinação dos resíduos sólidos urbanos gerados. Dessa forma, é fundamental realizarem-se os estudos visando novas formas de reutilização dos resíduos gerados pelas atividades industriais. Os resíduos sólidos urbanos e os pneus inservíveis gerados trazem conseqüências ao meio ambiente e às populações quando destinados inadequadamente. A destinação final dos resíduos sólidos urbanos é complexa, sendo sempre um grande desafio para as administrações públicas. Com a Política Nacional de Resíduos Sólidos (instituída pela Lei n 12.305/2010), tem-se um marco da preservação ambiental, coma a gestão e gerenciamento de resíduos sólidos, com a ordem de prioridade: não geração, redução, reutilização, reciclagem, tratamento dos resíduos sólidos e disposição final ambientalmente adequada dos rejeitos e prevê, de forma inteligente, a atribuição aos fabricantes de responsabilidade pelo retorno de produtos descartados pelos consumidores. Uma alternativa para minimizar estes aspectos e impactos ambientais é o tratamento térmico com aproveitamento energético. Este processo contribui para mais uma solução de destinação dos resíduos, proporcionado uma redução das áreas a serem utilizadas nos aterros sanitários e contribuindo como uma fonte de geração de energia elétrica / The increase in population, the growth of big cities, industrialization and consumption, have brought with them a kind of awareness about sustainability towards availability of energy and toward the destination of generated municipal solid waste. This way, it is primordial to carry out studies aiming to find new ways to reutilize the waste generated by industrial activities. The municipal solid waste and unusable tires produced cause serious consequences to the environment and to the population when these issues are improperly addressed. The final destination of the municipal solid waste is complex and it is always a big challenge to public management. With our National Policy of solid waste (established by the law number 12.305/2010).It consists of the administration and management of solid waste with the following order of priority: non-generation, reduction, reuse, recycling, treatment of solid waste and final environmentally appropriate disposal. With this we can foresee, in an intelligent way, a responsible plan for the return of goods discarded by consumers to the original manufacturers. An alternative to minimize these aspects and the negative environmental impacts caused is the usage of the thermal treatment with the good use of energy. This process contributes to another solution to the problem of the aforementioned waste, providing a reduction of landfill spaces and contributing to a new source of electrical energy generation

Este trabalho apresenta uma metodologia para a determinação do potencial de conservação de energia elétrica de usos finais, orientada para a análise de instalações de ensino, aplicável, também, a instalações comerciais em geral. Os usos finais considerados no trabalho são: iluminação, ar condicionado, microcomputadores pessoais e outros equipamentos elétricos. São apresentados procedimentos para o levantamento de dados e para a determinação do potencial de conservação de energia elétrica de cada uso final analisado, além de uma metodologia estatística para a análise de contas de energia elétrica. São definidos, também, indicadores do uso de energia elétrica bastante úteis em diagnósticos energéticos, permitindo estimar o potencial de conservação da instalação a partir da análise comparativa de seus índices com valores típicos obtidos em outros diagnósticos energéticos ou em publicações especializadas. A aplicação prática da metodologia é apresentada na forma de um estudo de caso, realizado em 1996 na Cidade Universitária Armando de Salles Oliveira - CUASO, o maior campus da Universidade de São Paulo – USP e um dos maiores do Brasil, localizado na cidade de São Paulo. Um volume considerável de informações é analisado e discutido em detalhes, fornecendo dados globais e desagregados em usos finais sobre as características de consumo e os potenciais de conservação de energia elétrica do campus. / This work presents a methodology for determining the potential of electric energy conservation of electricity end uses. The methodology is oriented to university premises, but it is also applicable to other types of installations. End uses considered in this work include lighting, air conditioning, personal computers and other electric devices. Procedures for data gathering and determination of conservation potential of each end use are presented. A statistical methodology for analyzing electricity bills is also presented. Furthermore, some useful indicators for energy diagnoses are developed. These indicators allow the estimation of the conservation potential of a given installation through comparison with typical values extracted from the other energy diagnoses or technical literature. The proposed methodology was applied in the main campus of University of São Paulo – USP, one of the largest in Brazil with some 30,000 undergraduate students. A large amount of data is analyzed and discussed, yielding global and specific indicators regarding end use characteristics and conservation potential within the campus.

Este trabalho tem como objetivo principal analisar o desenvolvimento da indústria da energia elétrica brasileira, a formação e composição das tarifas de energia elétrica e suas implicações e reflexos na economia em geral. Nesse sentido foi feito um breve histórico dessa indústria desde o ano de 1.993, que foi o ano em que se migrou de uma regulação de tarifas pelo sistema denominado custo do serviço para o sistema regulatório denominado price cap, ou seja, preços máximos pelo sistema de incentivos. Foi analisada essa linha regulatória que passou basicamente por dois governos sucessivos, com dois mandatos consecutivos. Fernando Henrique Cardoso no período de 1994 a 2003, que traçou as linhas mestras dessa regulação, com um programa de privatizações de empresas geradoras, transmissoras e distribuidoras de energia elétrica, delegando à iniciativa privada a maior parte da responsabilidade desse serviço. Nessa fase foram constituídas diversas agências reguladoras, sendo criada a ANEEL Agência Nacional de Energia Elétrica, com o objetivo de regular e mediar os interesses dos investidores e dos consumidores. Posteriormente, no governo Luis Inácio Lula da Silva, foi dada continuidade à esse tipo de regulação, com algumas modificações, basicamente na área do planejamento indicativo da expansão do sistema elétrico, que havia sido abandonado. Para analisar o comportamento das tarifas de energia elétrica desde o ano de 2005, foram eleitas cinco distribuidoras de energia elétrica representativas da diversidade geográfica brasileira, e comparado o crescimento do IGP-M com o crescimento das tarifas de consumidores típicos. / This dissertation has as main goal the analysis of the Brazilian electrical energy industry development, the formation and composition of electrical energy fees and its implication and reflexes in the economy as general. This way it is made a small historic of this industry since the year of 1993, which was the year that the regulation of fees by the system named custo do serviço migrated to the regulatory system named price cap, in other words, maximum prices by the system of incentives. This regulatory line, which basically went through two governments successively, was analyzed with two consecutive mandates, Fernando Henrique Cardoso during the period from 1994 to 2003, who wrote the main lines of this regulation, with a program of privatization of generation, transmission and distribution companies, delegating to the private initiative the major part of the responsibility of this service. In this phase were constituted many regulatory agencies, being also created the ANEEL - Agência Nacional de Energia Elétrica (Electrical Energy National Agency), with the goal to regulate and mediate the interests of the investors and consumers. Lately, during the government of Luiz Inácio Lula da Silva, it was given continuity to this kind regulation, with some modifications, basically in the area of planning indicating the expansion of the electrical system, which was abandoned. To analyze the behavior of the electrical energy fees since the year of 2005, were chosen five distributors of electrical energy representatives of the Brazilian geographical diversity and it was made the comparison between the growth of the IGP-M and the growth of the typical consumer fees.