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.

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.

Access to clean and affordable energy is a prerequisite for human development. In order to achieve access to sustainable energy for all innovation in rural electrification is needed. Decentralized renewable energy technologies in form of Solar Home Systems and Mini-grids possess the potential of electrifying a large number of rural households which cannot be connected to the national grid with local available energy sources. However, the deployment of Mini-grids is facing barriers such as a lack of private investments. By building on already existing SHSs swarm grids can enable households to trade electricity and use their excess electricity to supply additional loads. Swarm grids as an evolutionary bottom-up approach to electrification can overcome some of the obstacles regular Mini-grids face and play a vital role in improving electricity access. As part of this thesis a model has been developed which allows for simulating the electricity flow including line losses in swarm grids of any size on an hourly basis. The model facilitates the gaining of a better understanding for the impact global parameters (e.g. distance between households) have on the feasibility of swarm grids. A field trip to Bangladesh has been undertaken in order to obtain input data for simulating different cases in the model created. The simulations performed indicate that in a swarm grid the generated excess energy of SHSs which so far is wasted can supply the demand of households without SHS as well as commercial loads such as irrigation pumps. Overall the results point towards swarm grids being an innovation with the potential of improving rural electricity access by building on existing infrastructure.

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Reliable electricity supply remains a major problem in rural India nowadays. Renewable off-grid solutions have been applied in the last decades to increase power supply reliability but often failed to be feasible due to their high energy costs compared to the national grid. Grid Integrated Mini-grids with Storage (GIMS) can provide reliable power supply at an affordable price by combining mini-grids and national grid facilities. However, research on the techno-economic feasibility of these systems in the country is very limited and unavailable in the public sphere. This research project analysed three different aspects of the GIMS feasibility. First, the feasibility of the use of hybrid wind and solar Photovoltaic (PV) systems in GIMS was analysed by comparing the Levelised Cost of Electricity (LCOE) and Net Present Cost (NPC) of solar PV and hybrid PV/Wind GIMS systems. Second, the potential savings GIMS can offer due to the possibility of selling power to the grid were quantified by comparing the LCOE and NPC of the system with and without grid export. Lastly, the cost of reliability of the power supply was represented by the influence of the allowed percentage of capacity shortage on the total cost of the system. The analysis was carried out by means of the software HOMER and was based on three case studies in India. The results of this analysis showed that the use of hybrid systems could generate savings of up to 17% of the LCOE of the GIMS system in comparison to solar mini-grids. Moreover, power sales to the grid enabled LCOE savings up to 35% with respect to mini-grid without power sell-back possibility. In addition, the LCOE could be reduced in between 28% and 40% in all cases by enabling up to a 5% of capacity shortage in the system. / En tillförlitlig elförsörjning är ett stort problem på landsbygden i Indien. Elnätslösningar baserade på förnybara energikällor har undersökts under de senaste decennierna för att öka tillförlitligheten men har ofta misslyckats i genomförandefasen på grund av höga energikostnader jämfört med i det nationella nätet. Nätintegrerade mini-grids med energilagring (GIMS) kan ge tillförlitlig strömförsörjning till ett överkomligt pris genom att kombinera mini-grids och nationella elnätsanläggningar. Forskningen om den tekniskekonomiska genomförbarheten av dessa system i landet är emellertid mycket begränsad och otillgänglig inom den offentliga sfären. I den här studien analyseras tre olika aspekter av GIMS-genomförbarheten. För det första analyserades genomförbarheten av att använda hybrida vind- och solcellssystem i GIMS genom att jämföra ”Levelised Cost of Electricity” (LCOE) nivån och nuvärdeskostnaden (NPC) för solcellssystem (PV) och hybrid PV/Vind GIMS-system. För det andra kan de potentiella besparingar GIMS erbjuder, genom möjligheten att sälja elenergi till nätet, kvantifieras genom att jämföra LCOE och NPC i systemet med och utan ”nätexport”. Slutligen studeras kostnaden för tillförlitligheten hos strömförsörjningen i förhållande till accepterad kapacitetsbrist med avseende på systemets totala kostnad. Analysen har utförts med hjälp av mjukvaran HOMER och grundas på tre fallstudier i Indien. Resultaten av denna analys visar att användningen av hybridsystem skulle kunna generera besparingar på upp till 17% av LCOE i GIMS-systemet i jämförelse med enbart PV-baserade mini-grids. Försäljning av elenergi till nätet möjliggör LCOE-besparingar på upp till 35% med i förhållande till mini-grids utan möjlighet till export. Slutligen: LCOE kunde reduceras mellan 28% och 40% i samtliga fall genom att tillåta upp till 5% kapacitetsbrist i systemet.

Fuel supply issues are a major concern in remote island communities and this is an engineering field that needs to be analyzed in detail for transition to sustainable energy systems. Power generation in remote communities such as the islands of the Maldives relies on power generation systems primarily dependent on diesel generators. As a consequence, power generation is easily disrupted by factors such as the delay in transportation of diesel or rises in fuel price, which limits shipment quantity. People living in remote communities experience power outages often, but find them just as disruptive as people who are connected to national power grids. The use of renewable energy sources could help to improve this situation, however, such systems require huge initial investments. Remote power systems often operate with the help of financial support from profit-making private agencies and government funding. Therefore, investing in such hybrid systems is uncommon. Current electrical power generation systems operating in remote communities adopt an open loop control system, where the power supplier generates power according to customer demand. In the event of generation constraints, the supplier has no choice but to limit the power supplied and this often results in power cuts. Most smart grids that are being established in developed grids adopt a closed loop feedback control system. The smart grids integrated with demand side management tools enable the power supplier to keep customers informed about their daily energy consumption. Electric utility companies use different demand response techniques to achieve peak energy demand reduction by eliciting behavior change. Their feedback information is commonly based on factors such as cost of energy, environmental concerns (carbon dioxide intensity) and the risk of black-outs due to peak loads. However, there is no information available on the significant link between the constraints in resources and the feedback to the customers. In resource-constrained power grids such as those in remote areas, there is a critical relationship between customer demand and the availability of power generation resources. This thesis develops a feedback control strategy that can be adopted by the electrical power suppliers to manage a resource-constrained remote electric power grid such that the most essential load requirements of the customers are always met. The control design introduces a new concept of demand response called participatory demand response (PDR). PDR technique involves cooperative behavior of the entire community to achieve quality of life objectives. It proposes the idea that if customers understand the level of constraint faced by the supplier, they will voluntarily participate in managing their loads, rather than just responding to a rise in the cost of energy. Implementation of the PDR design in a mini-grid consists of four main steps. First, the end-use loads have to be characterized using energy audits, and then they have to be classified further into three different levels of essentiality. Second, the utility records have to be obtained and the hourly variation factors for the appliances have to be calculated. Third, the reference demand curves have to be generated. Finally, the operator control system has to be designed and applied to train the utility operators. A PDR case study was conducted in the Maldives, on the island of Fenfushi. The results show that a significant reduction in energy use was achieved by implementing the PDR design on the island. The overall results from five different constraint scenarios practiced on the island showed that during medium constrained situations, load reductions varied between 4.5kW (5.8%) and 7.7kW (11.3%). A reduction of as much as 10.7kW (15%) was achieved from the community during a severely constrained situation.