Organically Grown Microgrids: the Development and Simulation of a Solar Home System-based Microgrid

The United Nations has declared 2012 the ``International Year of Sustainable Energy for All''. A substantial portion of the world's population (some 1.3 billion people) currently live without electricity and development efforts to reach them are progressing relatively slowly. This thesis follows the development of a technology which can enable community owned and operated microgrids to emerge based solely on the local supply and demand of that community. Although this thesis ends with the technical analysis of a DC/DC converter, there is a significant amount of background to cover in order to properly understand the context in which it will be used. After providing an introduction into typical rural electrification efforts and pointing out some of the shortcomings of these projects, this thesis introduces some cutting edge efforts which combine solar home system technology with cellular technology and discusses the benefits of such a marriage of technology. Next, the research proposes some tweaks to this novel technology and provides a high-level economic demonstration of the spread of solar home systems in a community based on these modifications. It then takes this concept even further and proposes the addition of a DC/DC converter which could turn these individual solar home systems into a proper microgrid. This thesis elaborates on the development process of simulating such a microgrid in PSCAD, including the individual components of a solar home system and the specific task of designing the converter which would form the backbone of the proposed microgrid. The final simulations and analyses demonstrate a microgrid that is both technically and economically feasible for developing world applications

Innovation in Energy Systems

It has been a little over a century since the inception of interconnected networks and little has changed in the way that they are operated. Demand-supply balance methods, protection schemes, business models for electric power companies, and future development considerations have remained the same until very recently. Distributed generators, storage devices, and electric vehicles have become widespread and disrupted century-old bulk generation - bulk transmission operation. Distribution networks are no longer passive networks and now contribute to power generation. Old billing and energy trading schemes cannot accommodate this change and need revision. Furthermore, bidirectional power flow is an unprecedented phenomenon in distribution networks and traditional protection schemes require a thorough fix for proper operation. This book aims to cover new technologies, methods, and approaches developed to meet the needs of this changing field

Environmental Impact Assessment of Power Generation Systems at GSM (Global Systems for Mobile Communication) Base Station Site

Hybrid power systems were used to minimize the environmental impact of power generation at GSM (global systems for mobile communication) base station sites. This paper presents the comparative environmental impact assessment of a diesel gas (DG) and hybrid (PV/wind/hydro/diesel) power system for the base station sites. The assessment was based on theoretical modeling of the power stations using Hybrid Optimization Model for Electric Renewables (HOMER) software. The model was designed to provide an optimal system configuration based on hour-by-hour data for energy availability and demands. Energy source, energy storage and their applicability in terms of performance are discussed. The proposed hybrid (solar, wind & hydro) + DG system was simulated using the model which results in eight different topologies: hybrid (solar, wind & hydro) + DG, hybrid (solar & hydro) + DG, hybrid (wind & hydro) + DG, hydro only + DG, hybrid (solar & wind) + DG, solar only + DG, wind only + DG, DG. From the simulation results, it is shown that a 69% renewable energy penetration in the designed hybrid PV/wind/hydro/diesel system reduces the quantity of different air pollutants relative to the case of a diesel-only system. Details of the comparisons are presented

Innovation in Energy Systems

It has been a little over a century since the inception of interconnected networks and little has changed in the way that they are operated. Demand-supply balance methods, protection schemes, business models for electric power companies, and future development considerations have remained the same until very recently. Distributed generators, storage devices, and electric vehicles have become widespread and disrupted century-old bulk generation - bulk transmission operation. Distribution networks are no longer passive networks and now contribute to power generation. Old billing and energy trading schemes cannot accommodate this change and need revision. Furthermore, bidirectional power flow is an unprecedented phenomenon in distribution networks and traditional protection schemes require a thorough fix for proper operation. This book aims to cover new technologies, methods, and approaches developed to meet the needs of this changing field

Data-Driven Distributed Modeling, Operation, and Control of Electric Power Distribution Systems

The power distribution system is disorderly in design and implementation, chaotic in operation, large in scale, and complex in every way possible. Therefore, modeling, operating, and controlling the distribution system is incredibly challenging. It is required to find solutions to the multitude of challenges facing the distribution grid to transition towards a just and sustainable energy future for our society. The key to addressing distribution system challenges lies in unlocking the full potential of the distribution grid. The work in this dissertation is focused on finding methods to operate the distribution system in a reliable, cost-effective, and just manner. In this PhD dissertation, a new data-driven distributed ($D^3M$) framework using cellular computational networks has been developed to model power distribution systems. Its performance is validated on an IEEE test case. The results indicate a significant enhancement in accuracy and performance compared to the state-of-the-art centralized modeling approach. This dissertation also presents a new distributed and data-driven optimization method for volt-var control in power distribution systems. The framework is validated for voltage control on an IEEE test feeder. The results indicate that the system has improved performance compared to the state-of-the-art approach. The PhD dissertation also presents a design for a real-time power distribution system testbed. A new data-in-the-loop (DIL) simulation method has been developed and integrated into the testbed. The DIL method has been used to enhance the quality of the real-time simulations. The assets combined with the testbed include data, control, and hardware-in-the-loop infrastructure. The testbed is used to validate the performance of a distribution system with significant penetration of distributed energy resources

Reviewing energy system modelling of decentralized energy autonomy

Research attention on decentralized autonomous energy systems has increased exponentially in the past three decades, as demonstrated by the absolute number of publications and the share of these studies in the corpus of energy system modelling literature. This paper shows the status quo and future modelling needs for research on local autonomous energy systems. A total of 359 studies are roughly investigated, of which a subset of 123 in detail. The studies are assessed with respect to the characteristics of their methodology and applications, in order to derive common trends and insights. Most case studies apply to middle-income countries and only focus on the supply of electricity in the residential sector. Furthermore, many of the studies are comparable regarding objectives and applied methods. Local energy autonomy is associated with high costs, leading to levelized costs of electricity of 0.41 $/kWh on average. By analysing the studies, many improvements for future studies could be identified: the studies lack an analysis of the impact of autonomous energy systems on surrounding energy systems. In addition, the robust design of autonomous energy systems requires higher time resolutions and extreme conditions. Future research should also develop methodologies to consider local stakeholders and their preferences for energy systems

Opportunities and challenges for distributed generation with rooftop photovoltaic (PV) for Uganda: a case study crusader house, Kampala

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfillment for the degree of Master of Architecture (Sustainable Energy Efficient Cities). Johannesburg, 2018Distributed generation with rooftop PV technology is increasingly attracting attention as a strategy to enhance energy security for cities and as a critical climate-change mitigation intervention globally. In order to interrogate the strategy for a developing country context, the study applies a case study approach to explore responsive business models as well as related opportunities and challenges of DGRTPV deployment in Uganda, given the country’s advantage of abundant solar radiation as a result of favourable location across the equator. The study substantiates on the research question which focuses on rooftop PV business models, policy and legislation environment, energy efficiency interventions and financial mechanisms for expedited adoption of the technological innovation for commercial buildings in Uganda. In order to substantiate on the working hypothesis, interviews were conducted with key informants from the case study building-occupants and property manager, MEMD, ERA, KCCA, and UMEME. Data were collected using semi-structured interviews as well as energy audits and energy performance simulations of the case study building based on Excel and Design-Builder Energy-Plus software in order to ascertain performance under alternative intervention scenarios. The case study building consists of two blocks (the main block which is 5 storeys and the annex which is 4 storeys) and is grid-connected, but has standby generator with diesel consumption of up to 4,800 litres/year. The building was built in 1988 for the main block and 1993 for the annex and no energy efficiency interventions have been implemented so far. Overall, the baseline energy consumption is at 191,127.5kWh/year excluding diesel generation at 100,000kWh/year (2010 blackouts were 8 hours per day but at present, the generator is used for only 2 hours per day). Simulations, manual calculations, and economic feasibility appraisals were applied to guide on the viable energy efficiency and photovoltaic (PV) interventions. This resulted into viable energy reduction of 90,404.5kWh/year with a payback period of 0.6 months for lighting systems and additional energy efficiency interventions. Rooftop PV generation evaluation indicated an output of approximately 124,328.75kWh per year with the payback period of 7.6 years. Overall the study finds that the roof space area (610m2 ) of the building offers potential for generating surplus electricity which can be fed to the grid when responsive policy/regulatory environment is effected. The solar service business model is prioritised as the most viable given the current policy/regulatory landscape for Uganda as well as envisaged policy changes in the short term. Given Uganda’s low-carbon electricity generation mix, the study finds that opportunity for carbon emission reduction for the building would mainly arise from the displacement of the standby diesel generator whose current emission is estimated at 4,000kg/year. The study therefore concludes that DGRTPV deployment is now mature for scale-up in commercial buildings for Uganda.MT 201

Cost reduction strategies for the rural village energy concept

Tese de mestrado integrado em Engenharia da Energia e do Ambiente, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2013A agência internacional de energia estima que cerca de um quinto da população mundial não tem, acesso a eletricidade, particularmente em zonas rurais, maioritariamente na África Subsaariana e no Sudeste Asiático. A taxa de eletrificação rural na África Subsaariana era, em 2009, cerca de 14 % - consideravelmente abaixo da média mundial de 68%. As Nações Unidas apontam que a disponibilidade de energia (em especial energia elétrica) sustentável com baixo custo, tem o potencial de promover a educação, o acesso a água potável, a igualdade de géneros, diminuição da pobreza, e sustentabilidade ambiental – assim, a disponibilidade de energia pode ter um impacto direto e considerável na realização dos oito Objetivos de Desenvolvimento do Milénio. Os sistemas descentralizados de energia como o KUDURA podem providenciar energia limpa e água potável a comunidades rurais ou remotas. Apesar disso, este tipo de abordagens requerem um maior atual desenvolvimento, de modo a que se consiga aumentar a sua competitividade tecnológica e económica, e assim, a sua flexibilidade em ser distribuído em zonas rurais. O presente trabalho estuda duas tecnologias e case-studies em específico: Gaseificação de biomassa de pequena dimensão para a geração de eletricidade no Norte de Moçambique, utilizando casca de caju como combustível; e micro-hídrica para geração e armazenamento de eletricidade no litoral do Quénia – estas aplicações foram contempladas como possíveis formas de reduzir os atuais custos do KUDURA. Estas tecnologias são comparadas e analisadas com recurso ao software HOMER – uma ferramenta de análise para a avaliação de diferentes tecnologias e recursos energéticos e sua otimização com base em critérios económicos. O custo de energia para o sistema híbrido de gaseificação a biomassa é de 0.46 €/kWh, em oposição aos 0.53 €/kWh do sistema KUDURA. Estes resultados mostraram ser sensíveis a variáveis como o preço do caju, a potência do sistema solar fotovoltaico e, mais importante, sensíveis ao custo de operação e manutenção – em particular, o salário dos técnicos locais. Em relação ao sistema hídrico de fio-de-água proposto, é mostrado nesta análise que o custo de energia situa-se na gama de 0.17-0.27 €/kWh, tornando este sistema particularmente adequado a regiões com um recurso hídrico abundante. Por outro lado, como opção de armazenamento hídrico de energia através de bombagem de água, os resultados simulados sugerem que pode não tornar-se economicamente competitivo com as formas tradicionais de armazenamento de energia eletroquímica.The International Energy Agency estimates that about one-fifth of the world’s population does not have access to electricity in particular in rural areas, mainly in sub-Saharan Africa and South Asia. In 2009, the rate of rural electrification in sub-Saharan Africa was 14%, considerably below the global average of 68%. The United Nations has found that access to affordable and sustainable energy, particularly electricity, can promote education, access to potable and safe water, gender equity, poverty’s end and environmental sustainability, thus electricity can have a direct impact on achieving the eight Millennium Development Goals. Decentralised energy systems, like the KUDURA concept, have the ability to provide clean energy and potable water to rural or remote communities. Nevertheless, these approaches require further development to increase its cost-effectiveness and deployment flexibility. The present work looks at two specific technologies and case-studies: small-scale biomass gasification for power generation using cashew nut shells as feedstock for the northern region of Mozambique; and micro hydro-power for power generation and energy storage for coastal Kenya – which were seen as possible cost reduction routes. These technologies are compared and analysed through the use of the HOMER software, an analytic tool for evaluating different energy technologies and resources and optimization based on economic criteria. The levelised cost of energy (LCOE) of the optimized hybrid biomass gasification system may reach €0.46/kWh, significantly below the KUDURA baseline cost of €0.53/kWh. These results are sensitive to variables such as the feedstock cost, the photovoltaic array required and, most importantly, to the costs associated to operation and maintenance, in particular the salaries of the local technicians. Regarding the proposed run-of-the-river-type hydro system, it is shown that it may achieve a LCOE in the range of €0.17-0.27/kWh, making it particularly suitable for regions with an abundant hydro resource. On the other hand, as a form of energy storage via pumped water storage, the simulation results suggested it cannot become competitive with standard electrochemical energy storage