Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: This thesis discusses the development of a 5 kVA single phase AC voltage regulator, specifically designed to assist in the reduction of electrification costs in sparsely populated rural areas. The voltage regulator is based on a solid state auto-transformer tap changer, designed to be robust and maintenance free. Electrification cost savings can be realized if the length of the LV network can be extended to reach more households. To accomplish this, a voltage regulator can be installed onto the extended LV feeder at the point where the LV voltage will drop below the minimum valid voltage, thereby boosting the voltage downstream and enabling more customers to be connected. A variety of voltage regulator topologies were investigated to obtain the best topology for the application. The voltage regulator design is discussed in detail with careful attention given to the power loss incurred, surge voltage protection requirements, protection coordination with the existing LV network and the thermal design requirements. An electronic controller based on a digital signal processor together with an appropriate power supply is designed and built. The software to control the voltage regulator is developed, integrated with the hardware and debugged. The complete voltage regulator is evaluated through extensive laboratory testing and field trials are performed to verify the performance of the device. / AFRIKAANSE OPSOMMING: Hierdie tesis bespreek die ontwikkeling van ‘n 5 kVA, enkelfase, wisselstroom spannings reguleerder, spesifiek ontwerp om koste besparings te bewerkstellig in die elektrifisiëring van yl bevolkte landelike gemeenskappe. Die spannings reguleerder se ontwerp is gebaseer op ‘n outo-transformator tap wisselaar met vaste toestand skakelaars, om sodoende robuust en instandhoudings vry te funksioneer. Elektrifisiërings koste besparings is moontlik indien die laag spannings distribusie kabel verleng kan word, om sodoende elektrisiteit aan meer huishoudings te voorsien. Om dit mootlik te maak kan ‘n spannings reguleerder geinstalleer word op die punt waar die kabel spanning onder die minimum toegelate spanning daal. Sodoende word die spanning weer verhoog aan al die huishoudings wat aan die verlengde gedeelte van die kabel verbind is. ‘n Verskeidenheid uiteenlopende spannings reguleerder topologieë is ondersoek om die beste topologie vir die toepassing te identifiseer. Die ontwerp van die spannings reguleerder is baie deeglik bespreek en spesifieke aandag is gegee aan die verliese, spits opwelling spannings beveiliging, sinkronisasie met die huidige laag spannings netwerk se beveiligings meganismes en die termiese ontwerp van die stelsel. ‘n Elektroniese beheerder, gebaseer op ‘n digitale sein verwerker, tesame met ‘n toepaslike kragbron is ontwerp en gebou. Die nodige sagteware om die spannings reguleerder te beheer is ontwikkel, geintegreer met die hardeware en ontfout. Die volledige spannings reguleerder is ontleed deur intensiewe toetse in die laboratorium en toets installasies op laag spannings netwerke, om sodoende die nakoming van die werks verrigting vereistes van die toestel te bevestig.

Die anspruchsvollen Zielsetzungen zum CO2-Ausstoß von Kraftfahrzeugen verlangen immer stärker nach hocheffizienten Fahrzeugkonzepten und werden zukünftig zu deutlich höheren Elektrifizierungsanteilen der Antriebe führen. Die große Herausforderung liegt dabei in der Lösung des Zielkonfliktes zwischen voll elektrischem Fahren und erstfahrzeugtauglicher Reichweite. Im Rahmen eines Forschungsprojektes zur Konzeption von Hybridfahrzeugen hat die BMW Forschung ein Konzeptfahrzeug entwickelt, das im urbanen Bereich emissionsfrei betrieben werden kann und dennoch alltagstauglich für spontane längere Fahrten nutzbar ist (Abbildung 1). Die für dieses Projekt abgeleiteten Ziele waren ein Verbrauch von < 2,5 l im Ladungserhaltungsbetrieb, eine E-Reichweite von 100 km, eine BMW-adäquate Beschleunigung von < 8 sec von 0 auf 100 km/h, eine erstfahrzeugtaugliche Höchstgeschwindigkeit von 180 km/h, ein Raumangebot auf Niveau heutiger viersitziger Coupés im Kompaktsegment und eine Gesamtreichweite von 1.000 km (Eiletz 2015a). Im Rahmen des Beitrags werden sowohl Prozess und Vorgehensweise bei der Gestaltung des Hocheffizienz-Konzeptfahrzeugs als auch die Ergebnisse des Forschungsprojektes dargelegt.

Master of Science / Department of Electrical and Computer Engineering / Anil Pahwa / In Afghanistan, electricity is mostly generated by hydroelectric, diesel and natural gas generators. A significant amount of electricity also is imported from neighboring countries. Accessibility of electricity is mostly limited to the capital and main towns. The government of Afghanistan and other development organizations, such as The United States Agency for International Development (USAID) and Deutsche Gesellschaft für Internationale Zusammenarbeit (German Agency for International Cooperation “GIZ”), are striving to develop accessibility of electricity to remote communities by supporting the local population of people to enhance living conditions. Although some of these remote communities are served by local diesel fuel generators for just a couple of hours during the night, still most communities do not have access to electricity and they are using wood and kerosene as major sources of energy in cooking, heating and lighting. For those remote communities who are served by local diesel fuel generators, the cost of electricity is much higher than from the national grid. On the other hand, grid extensions are too expensive and, in some cases, impossible for such communities because of the geographical features of Afghanistan. Afghanistan is a mountainous country which receives a significant amount of snow during the winter and once it melts the water runs into rivers, lakes and streams. Therefore mostly it does not face any shortage of running water during the year. Also Afghanistan has plentiful wind and solar energy. Therefore, small hydro-power, wind turbine and solar energy are attractive renewable energy sources for remote communities. The development of such a hybrid power system is a complex process and technical expertise is essential in design and construction phases. The main challenges are the high cost of civil works and equipment, technical expertise for design and construction and encouragement of local people for the support of the project. This report will give an insight into design, cost-effectiveness and feasibility of the system using HOMER in order to encourage private investors and local community people to take advantage of this potential available in Afghanistan and be convinced of the sustainability for investments in micro-hydropower, wind and solar.

Este estudo faz uma abordagem da produção de energia hidroelétrica sob a perspectiva da Geografia crítica e releva que a água é um elemento natural em todas as manifestações, sendo o seu uso o que a transforma em recurso natural e produtivo. A água não é fonte direta de energia elétrica, ela é condição natural de um lugar. A construção de usinas hidroelétricas coloca-a em circuitos de fixos, fazendo com que se integrem aos circuitos produtivos. O levantamento desses equipamentos, especialmente as grandes usinas construídas no Brasil com essa finalidade, é importante para a Geografia do ponto de vista teórico, pois têm grande fixidez no território e são agregadas a ele como verdadeiras próteses territoriais. Sua análise serve ao ordenamento do espaço, que é fundamental para o planejamento do País. / This study approaches the production of hydroelectric power from the perspective of critical geography and emphasizes that water is a natural element in all of its manifestations, being that its use transforms it into a natural and productive resource. Water is not a direct source of electricity. It is a natural condition of a place. The construction of hydroelectric power plants puts water in fixed circuits, making it a part of productive circuits. The data collection of these equipments, especially large hydropower plants in Brazil, is important for geography from a theoretical point of view because they have great fixity on the territory and are aggregated as true territorial prostheses. Their analysis serves as spatial planning, which is crucial for the planning of the country.

Este trabalho apresenta a implantação de sistemas fotovoltaicos domiciliares (SFDs) na comunidade de São Francisco do Aiucá, localizada na Reserva de Desenvolvimento Sustentável Mamirauá (RDSM), no Estado do Amazonas. A instalação desses sistemas é o resultado de um projeto financiado com fundos setoriais, CT-Energ/MME/CNPq, para atendimento de comunidades isoladas na Região Norte. O projeto foi desenvolvido no contexto da Resolução Normativa ANEEL Nº 83, Sistemas Individuais de Geração de Energia Elétrica com Fontes Intermitentes (SIGFIs), de 20 de setembro de 2004. Foram instalados 19 sistemas, que estão em operação desde agosto de 2005. São mostradas as características técnicas dos sistemas e os resultados operacionais do projeto. Em particular, este trabalho detalha as ações da implantação: o planejamento, a execução das tarefas, o monitoramento do desempenho dos sistemas e as atividades de capacitação dos usuários e técnicos locais; destacando e documentando alguns problemas pontuais e as soluções encontradas para contorná-los. / This work presents the implantation of solar home systems (SHS) in the community of São Francisco do Aiucá, located in the Reserva de Desenvolvimento Sustentável Mamirauá (Mamirauá Reservation Sustainable Development), in the Amazonas State, Brazil. The installation of these systems is the result of a project financed with sectorial funds, CT-Energ/MME/CNPq, to assist isolated communities in the Northern Region of Brazil. The project was developed in the context of the Normative Resolution ANEEL Nº 83, from September 2004, Electric power Generation by Individual Systems with Intermittent Sources (SIGFIs). A total of 19 systems were installed, which are in operation since August, 2005. Technical characteristics of the systems and the operational results of the project are presented. In particular, this work details the actions of the implementation: the planning, the execution of the tasks, the monitoring of the systems\' performance and the activities of qualification of the users and local technicians; emphasizing and documenting some individual problems and the solutions found to contour them.

The transition from one energy system to another has been analysed by many researchers especially in the context of developed countries. Community renewable energy transition in rural areas is largely under-researched, particularly in developing countries. This study developed a model based on indicators from transition theory and concepts to assess the transformative potential of the processes and governance approaches to community renewable energy in accelerating energy and sustainability transition in off-grid communities in Nigeria. The exploratory research adopted a case study approach and analysed renewable energy planning and decision-making processes as well as evaluated the development of a pilot community renewable energy project in Shape rural community in Nigeria. In addition to documentary evidence, the study gathered data primarily by interviewing 24 relevant actors in the Nigerian electricity industry as well as actors involved in the pilot community renewable energy project. The study reveals that the processes and governance approaches adopted are in line with transition theory and have the potential of contributing to the transformation of the rural electricity provision in Nigeria. However, there is still a long way to go for Nigeria to effectively implement an integrated governance approach capable of accelerating the transition processes. The study found that community renewable energy is motivated by several determinants including: the lack of energy accessibility; removing carbon emissions; meeting environmental obligations; achieving energy security; and, addressing cracks in the current system of rural electrification. The study further found a lack of local initiatives at the grassroots level that can add pressure to make the transition happen. The study found the establishment of an arena for the identification of the challenges facing rural communities and development of strategies. However, some prominent actors are not involved in both strategic decision-making and the implementation process. Of concern, the study revealed a lack of clearly defined responsibilities with most of the government agencies carrying out renewable energy activities independently. Similarly, the study found several barriers which are classified as: actor; interaction; institutional; infrastructural; and, socio-political that are challenging the successful transition to community renewable energy. This work contributes to current attempts to operationalise transition theory and concepts to assess on-going transition processes and governance. This is a significant contribution to the literature because it helps in linking theoretical development with sustainability in practice in a developing country context. The study may assist policy makers, communities and other relevant stakeholders in designing an integrated governance framework for renewable energy transition in rural areas.

La remise en question du mode de développement des sociétés humaines a, sur ces 40 dernières années, profondément transformé le contexte énergétique mondial, instaurant alors un nouveau cadre politique permettant l’essor spectaculaire des énergies renouvelables. Par ailleurs, si l’électricité apparaît comme un vecteur fondamental du développement humain, le contexte des populations majoritairement rurales d’Afrique subsaharienne incite à la recherche d’alternatives énergétiques adaptées. En substance, si les ressources renouvelables peuvent répondre de manière pertinente au défi de l’électrification décentralisée des zones rurales de la région, elles doivent également représenter une solution technique et économique crédible, avant d’être politique.La République de Djibouti, petit pays situé dans la corne de l’Afrique, symbolise parfaitement le défi socio-énergétique de l’ensemble de la région, et des populations rurales en particulier. Avec un pays pauvre en ressources traditionnelles mais présentant a priori un gisement solaire intéressant, nous avons alors privilégié l’étude des systèmes photovoltaïques (PV) dans le cadre de l’électrification décentralisée des populations rurales du pays. Comme d’autres ressources, ces systèmes, bien que reposant sur une technologie relativement ancienne, ont réellement pris leur essor au début des années 2000 avec les mesures incitatives du Protocole de Kyoto.Évaluer la pertinence de la technologie photovoltaïque nécessitait, dans un premier temps, d’estimer le niveau et la répartition de la ressource solaire au sein du pays. Pour cela, nous avons construit un atlas de l’irradiation solaire horaire incidente sur le territoire, pour la période 2008-2011, à partir d’un modèle satellitaire de rayonnement. Afin de valider les estimations issues de cet atlas, nous les avons comparées aux mesures in situ relevées par deux stations météorologiques temporaires déployées, entre 2010 et 2013, sur quatre sites présentant des caractéristiques distinctes. Finalement, la carte annuelle extraite de l’atlas a confirmé que le gisement solaire du pays, avec une irradiation moyenne de 5,87kWh/m² par jour, constituait l’un des plus importants au monde.Si les modèles utilisant des données satellitaires permettent de retrouver le flux solaire incident au sol, ils ne tiennent en revanche pas compte des effets du relief local sur ce dernier. Ainsi, afin de tenir compte des effets d’ombrage engendré par le terrain, nous avons développé une procédure dite de désagrégation, couplant l’utilisation d’un maillage numérique d’altitude aux cartes de rayonnement issues du modèle satellite. Pour ce faire, nous avons élaboré un modèle théorique pour retrouver l’horizon autour d’un point donné, et validé celui-ci à l’aide d’une campagne de mesures topographiques en Corse. En corrigeant ensuite le rayonnement à l’aide de cet horizon pour chaque pixel du maillage d’altitude, nous avons pu enrichir le niveau de l’information fournie par la cartographie de l’irradiation globale.Bien que le gisement solaire soit l’indicateur principal du potentiel photovoltaïque, il est également nécessaire de considérer des paramètres secondaires, éléments de technologie et caractéristiques environnementales, qui permettent d’évaluer avec précision l’énergie électrique produite par un système PV quelconque. En combinant l’utilisation de différents modèles, nous avons ainsi pu intégrer à l’estimation finale du productible l’influence du rayonnement et de la température sur le rendement de conversion d’un module photovoltaïque. Nous avons ainsi construit une cartographie du productible PV qui, couplée à une évaluation multicritère de la pertinence de la technologie PV vis-à-vis des alternatives énergétiques classiques en matière d’électrification rurale, est destinée à faciliter la prise de décision pour les différents acteurs, publics ou privés, du domaine de l’énergie. / Over the 40 past years, growth of renewable energies benefited of the new world energy frame, which resulted of the questioning about what development of human societies had to be. Furthermore, although human development comes with electricity, the rural condition of many populations of sub-Saharan Africa incites us to look for suitable power supply alternatives. Eventually, in this specific context, renewable energies can represent a reliable solution to the off-grid electrification of rural peoples. However, this solution has to be economical and technical, and not only political.The Republic of Djibouti is a little developing country located in the Horn of Africa which perfectly symbolizes the social and energy challenges of rural populations in Sub-Saharan Africa. Instability and limitation of the existing electrical grid, fuel cost and lack of fossil resources point to the geographically diffused solar resource as probably the best way to improve human development and reduce poverty of Djiboutian rural peoples. Therefore, we have considered the study of photovoltaic (PV) systems within the rural off-grid electrification frame.Firstly, in order to evaluate relevance of these systems, it was necessary to estimate level and repartition of the solar resource across the country. So we developed a solar atlas, i.e. cartography of the hourly solar irradiation reaching the ground, based on satellite-derived irradiance estimates retrieved between 2008 and 2011. For assessing the atlas quality, we compared irradiation estimates with ground measures retrieved on 4 different sites by 2 temporary weather stations deployed between 2010 and 2013. Finally, yearly map extracted from the atlas showed that, with a daily mean irradiation of 5,87kWh/m².day, the solar potential of Djibouti is one of the most significant in the world.Satellite models are useful for determining solar irradiance at ground level but they don’t take into account local topography effects. In order to incorporate these shading effects to the satellite-derived irradiance maps, and so improve irradiance accuracy and spatial resolution, we used a Digital Elevation Model (DEM). Firstly, this disaggregation process was based on the development of a new fast horizon algorithm which was assessed by means of topographic measures in Corsica Island. Then, by correcting irradiance with this horizon for each pixel of the DEM, we improved geographic information of the solar irradiation atlas.Although solar resource is the first indicator of the photovoltaic potential, other elements, as environmental parameters or endogenous characteristics of photovoltaic modules, also have to be taken into consideration for precisely estimating energy produced by a PV system. Hence, by means of different models, we evaluated influence of irradiance and temperature onto the conversion efficiency of a PV generator to finally retrieve the atlas of the PV potential across the country. In conclusion, by combining this cartography to a multi-criteria approach comparing relevance between PV systems and classical power supply systems within the rural electrification scheme, we developed the first photovoltaic decision making tool of the country intended for all officials who are acting in the energy field.

Energy poverty and lack of access to electricity is a global problem which is recognised in the sustainable development goal 7. Today 1.2 billion people live without access to electricity and most of them are situated in Sub-Saharan Africa where biomass still constitutes the main source of energy. Rural areas are unproportionally affected by this throughout SSA since grid-extension has been slow and most rural dwellers are not connected to any form of electricity grid. Extending the grid to more isolated rural areas may however be economically and politically infeasible which is why off-grid solutions is an attractive solution to close the energy poverty gap. Off-grid solar energy has during recent years been increasingly promoted as viable solution to provide clean, affordable and accessible energy to rural households in SSA. While there is extensive research available on the economic feasibility and socioeconomic impacts of off-grid solar energy, there has been limited research with explicit focus on how livelihoods of rural households in SSA have been impacted from a sustainable livelihood perspective. This case study on Tanzania argues that the sustainable livelihoods perspective is crucial in getting a holistic understanding of how off-grid solar energy has impacted rural households in SSA. Through qualitative interviews with a number of households, businesses and social services in three rural villages located in the Tanga region, this study found that off-grid solar energy overall seemed to have a positive impact on the communities and the livelihoods of individual households. However, some concerns are also raised with the sustainability of off-grid solar energy. While it has great recognised potential and direct impact, some key challenges were identified as issue of energy security for the household and concerns of economic feasibility in the solar energy sector.

Recentemente, muitas mudanças vêm ocorrendo na forma como a energia elétrica é gerada e distribuída, criando com isso oportunidades de utilizar os recursos disponíveis in loco de forma mais eficiente, atuando juntamente com sistemas centralizados convencionais, para o atendimento das necessidades energéticas. Neste contexto, as minirredes de energia são consideradas pontos chaves para melhorar a confiabilidade e a qualidade da energia, aumentar a eficiência do sistema elétrico como um todo, viabilizar aos consumidores finais a possibilidade de uma certa independência da rede e uma participação mais ativa no mercado de energia elétrica. No entanto, a aplicação de tais topologias ainda não superou todas as barreiras para que todos os benefícios possam ser apreciados. Há ainda perguntas a serem respondidas sobre como lidar com as especificidades e os aspectos operacionais de minirredes, tanto em operação normal quanto em operação anômala, que são fundamentais para a sustentabilidade de longo prazo dos sistemas. Este trabalho discute aspectos relacionados à operação de minirredes, tanto em sistemas isolados quanto em sistemas conectados à rede da concessionária. No caso de sistemas isolados, a abordagem leva em consideração os riscos associados aos projetos voltados para eletrificação rural e discute questões não restritas ao projeto inicial, mas também à operação destes tipos de sistemas. No caso de sistemas conectados, são discutidas tendências relacionadas às topologias de utilização destes sistemas para operação conjunta com a rede elétrica. Um algoritmo para controle de minirredes em diferentes níveis hierárquicos é proposto. Este algoritmo serve como base para o controle da plataforma de interação de agentes distribuídos, montada no Laboratório de Sistemas Fotovoltaicos da Universidade de São Paulo para testes em equipamentos reais e para a formação de recursos humanos. / Recently, many changes are taking place in the way energy is generated and distributed, thus creating opportunities to utilize the resources available on site more efficiently, working along with conventional centralized systems, to meet energy needs. In this context, mini-grids are considered key points to improve the reliability and power quality, increase the efficiency of the electric system as a whole, enable end consumers to have a certain independence from the grid and a more active participation in the electricity market. However, the application of such topologies has not yet overcome all barriers so that all their benefits can be appreciated. There are still questions to be answered on how to deal with the specificities and operational aspects of micro-grids in both normal and anomalous operation, which are fundamental to the long-term sustainability of power systems. This work discusses aspects related to micro-grids in both isolated and grid-connected operation modes. In the case of isolated systems, the approach takes into account the risks associated with rural electrification projects and discusses issues not restricted to the design, but also to the operation of these types of systems. In the case of grid-connected systems, trends related to the topologies to be used for joint operation with the power grid are discussed. An algorithm to control micro-grids at different hierarchical levels is proposed. This algorithm serves as a basis for the control of the platform for the interaction of distributed agents assembled at the Laboratório de Sistemas Fotovoltaicos of the Universidade de São Paulo to be used for tests on real equipment and for capacity building.

Orientador: Prof. Dr. Federico Bernardino Morante Trigoso / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Energia, 2014. / Neste trabalho se determinou a viabilidade do uso de sistemas de iluminação LED em sistemas fotovoltaicos domiciliários (SFD) instalados em áreas rurais, considerando parâmetros econômicos e luminotécnicos como iluminância, fluxo luminoso, consumo de energia e custos iniciais tanto dos SFD's como dos sistemas de iluminação LED. A análise da variação dos custos iniciais do sistema fotovoltaico foi realizada através de uma simulação realizada no programa Homer Energy. O uso deste programa permitiu determinar como se modificaria o dimensionamento dos SFD's e o consumo de energia com a inserção dos sistemas de iluminação LED. Deste trabalho se conclui que dependendo da perspectiva avaliada, custo inicial do sistema de iluminação LED ou custo e uso do excedente de energia gerado pela troca de tecnologia, seria viável ou não a inserção de sistemas de iluminação LED em SFD's. Já para a análise comparativo das características luminotécnicas entre os sistemas de iluminação LED e as lâmpadas CFL se utilizou o programa DIALux. Por outro lado, devido à falta de estudos que abordaram transversalmente os impactos ambientais e socioeconômicos gerados pelas lâmpadas CFL e LED se considerou importante identifica-los. Desta análise se conclui que estes impactos dependem de fatores como a localização geográfica, renda mensal e acesso à tecnologia, materiais de fabricação das lâmpadas entre outros. Além disso, deduz-se que os resultados apresentados nesta dissertação mudariam drasticamente se esta análise fosse realizada em áreas urbanas. / This work established the feasibility of using LED lighting systems for home-based photovoltaic systems (SFD) installed in rural areas, considering economic and lighting parameters as luminance, luminous flux, energy consumption and initial costs of both systems as SFD's LED lighting. The variation of the initial cost of the PV system was performed through a simulation in Homer Energy program. The use of this program has allowed to determine how to modify the design of SFD's power consumption with the inclusion of LED lighting systems. This work is concluded that depending on the perspective assessed, initial cost of LED lighting or cost and use of excess energy generated by the exchange of technology system would be viable or not the inclusion of LED lighting systems in SFD's. As for the comparative analysis of lighting characteristics of lighting systems LED and CFL lamps are used the DIALux program. Moreover, due to the lack of studies that have focused in the environmental and socioeconomic impacts generated by CFL and LED lamps was considered important to identify them. This analysis concludes that these impacts depend on factors such as geographic location, monthly income and access to technology, materials and other manufacturing lamps. Furthermore, it appears that the results presented in this thesis would change dramatically if this analysis were conducted in urban areas.