Power generation from solar energy has significantly increased, and the growth is projected to continue in the foreseeable future. The main challenge of dealing with solar energy is its intermittent nature. The received irradiation energy of the sun on the earth's surface can fluctuate in a matter of seconds and cause voltage issues to power systems. Considering the high growth rate of solar photovoltaic (PV) resources, it is essential to be prepared to encounter and manage their high penetration levels. Currently, simplified approaches are used to model the impacts of cloud shadows on power systems. Using outdated standards also limits the penetration levels more than required. Approximately 40% of the new PV installations are residential, or installed at a low voltage level. Currently, all components between utility distribution transformers and customers/loads are either ignored or modeled with oversimplification. Furthermore, large PV systems require a considerable amount of land. However, point sensor models are currently used to simulate those systems. With a point model, the irradiance values measured at a point sensor are used to represent the output of a large PV system. However, in reality, clouds cover photovoltaic resources gradually and if the solar arrays are widespread over a large geospatial area, it takes some time for clouds to pass over the solar arrays. Finally, before 2014, participation of small-scale renewable resources was not allowed in controlling voltage. However, they can contribute significantly in voltage regulation. The main objective of this dissertation is to address the abovementioned issues in order to increase the penetration levels as well as precisely identify and locate voltage problems. A time-series analysis approach is used in modeling cloud motion. Using the time-series approach, changes of the received irradiation energy of the sun due to cloud shadows are simulated realistically with a Cloud Motion Simulator. Moreover, the use of the time-series approach allows implementation of new grid codes and standards, which is not possible using the old step change methods of simulating cloud impacts. Furthermore, all electrical components between utility transformers and customers are modeled to eliminate the inaccuracy due to using oversimplified models. Distributed PV models are also developed and used to represent large photovoltaic systems. In addition, the effectiveness of more distributed voltage control schemes compared to the traditional voltage control configurations is investigated. Inverters connect renewable energy resources to the power grid and they may use different control strategies to control voltage. Different control strategies are also compared with the current practice to investigate voltage control performance under irradiation variations. This dissertation presents a comprehensive approach to study impacts of solar PV resources. Moreover, simulation results show that by using time-series analysis and new grid codes, as well as employing distributed PV models, penetration of solar PV resources can increase significantly with no unacceptable voltage effects. It is also demonstrated that detailed secondary models are required to accurately identify locations with voltage problems. / PHD

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 um estudo de medições e simulações de fluxo harmônico na Usina Solar Fotovoltaica do Estádio Mineirão em Belo Horizonte/MG. O objetivo foi verificar o comportamento dos inversores solares fotovoltaicos na geração de harmônicos e a atenuação ocorrida pela agregação de múltiplos inversores. Para isso, foram realizadas medições em seis pontos estratégicos da usina investigada, por meio de analisadores de qualidade de energia, o que possibilitou a verificação do comportamento da usina em horários distintos e condições climáticas diversas. Foi avaliada a injeção de harmônicos no sistema elétrico pelos inversores e comparados os valores com os limites previstos em normas, procedimentos e recomendações vigentes. Além disso, o modelo completo da usina foi desenvolvido e simulado utilizando os softwares OpenDSS, ANAH e PowerFactory para análise harmônica e sua validação com os dados de medição. Os resultados obtidos indicam boa conformidade das medições e adequações dos modelos desenvolvidos. / This work presents a study of harmonic measurements and flow simulations in Photovoltaic Solar Plant of the Mineirao Stadium in Belo Horizonte/MG. The objective was to verify the behavior of photovoltaic solar inverters in the generation of harmonics and the attenuation occurred by the aggregation of multiple inverters. For this, measurements were performed on six strategic points of the investigated plant through power quality analyzers, allowing the verification of the plant's behavior at different times and different climates. It was evaluated the injection of harmonics in the electrical system for inverters and compared the values with the limits laid down in standards, procedures and current recommendations. In addition, the complete model of the plant was developed and simulated using the OpenDSS, ANAH and PowerFactory softwares to harmonic analysis and its validation with the data measurement data. The results indicate good agreement between measurement and developed models.

Diffusion of microgeneration technologies, particularly rooftop photovoltaic (PV), represents a key option in reducing emissions in the residential sector. This thesis uses a uniquely rich dataset from the burgeoning residential PV market in Texas to study the nature of the consumer’s decision-making process in the adoption of these technologies. Focusing on the financial metrics and the information decision makers use to base their decisions upon, I study how the leasing and buying models affect individual choices and, thereby, the adoption of capital-intensive energy technologies. Overall, the leasing model is found to more effectively address consumers’ informational requirements. Contrary to previous studies, buyers and lessees of PV are not found to substantially differ along socio-demographic variables, though they do differ significantly along cash availability, levels of environmental concern, and relative importance of financial aspects. Instead, the leasing model has opened up the residential PV market to a new, and potentially very large, consumer segment—those with a tight cash flow situation. / text

Submitted by Maria Suzana Diniz (msuzanad@hotmail.com) on 2015-11-05T15:16:09Z No. of bitstreams: 1 arquivototal.pdf: 1606899 bytes, checksum: 90c3cfba727598d80a41bea38edd76ef (MD5) / Made available in DSpace on 2015-11-05T15:16:09Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1606899 bytes, checksum: 90c3cfba727598d80a41bea38edd76ef (MD5) Previous issue date: 2014-08-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The present work aims to simulate the effects of connecting photovoltaic power plants in the active energy losses of the distribution system at the west of the state of Paraíba. Initially was done the modeling of the distribution system, which has one supply point, 20 substations 69/13.8 kV and 25 distribution lines 69 kV. For network analysis was used the Newton-Raphson method for solution of power flow after and before the insertion of photovoltaic plants and finally an optimized allocation of solar photovoltaic plants has been proposed with the aim of minimizing losses of active power using genetic algorithms. / O presente trabalho tem como objetivo simular os efeitos da conexão de centrais geradoras fotovoltaicas nas perdas de energia ativa do sistema de distribuição do oeste do estado da Paraíba. Inicialmente foi realizada a modelagem do sistema de distribuição, que possui um ponto de suprimento, 20 subestações rebaixadoras 69/13,8 kV e 25 linhas de distribuição 69 kV. Para análise da rede foi utilizado o método de Newton-Raphson para solução do fluxo de potência do sistema antes e depois da inserção das centrais fotovoltaicas e por fim foi proposta uma alocação otimizada das centrais solares fotovoltaicas com o objetivo de minimização das perdas de energia ativa utilizando algoritmos genéticos.

Submitted by JORGE MARIO AVELLA RUIZ null (jmaverui@gmail.com) on 2016-08-22T20:10:15Z No. of bitstreams: 1 avella_jm_me_guara.pdf: 2916680 bytes, checksum: 8dc01146f5007c3e858113a4d41eeab3 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-08-24T17:05:52Z (GMT) No. of bitstreams: 1 avellaruiz_jm_me_guara.pdf: 2916680 bytes, checksum: 8dc01146f5007c3e858113a4d41eeab3 (MD5) / Made available in DSpace on 2016-08-24T17:05:52Z (GMT). No. of bitstreams: 1 avellaruiz_jm_me_guara.pdf: 2916680 bytes, checksum: 8dc01146f5007c3e858113a4d41eeab3 (MD5) Previous issue date: 2016-08-01 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Atualmente, governos de todo o mundo estão se preocupando pelos efeitos das economias, indústrias e políticas no meio ambiente, criando regulações para fomentar a utilização de tecnologias menos poluidoras. No Brasil, a Agência Nacional de Energia Elétrica (ANEEL) é o ente federal de promover a implementação de fontes renováveis para a geração de eletricidade. A ANEEL mediante a resolução Nº 482/2012 permite aos usuários finais a instalação de tecnologias renováveis para produzir eletricidade para suas cargas elétricas, incrementando assim a porcentagem de energias alternativas na matriz energética nacional, considerando também os projetos renováveis de grande escala. Neste trabalho, realizou-se um estudo para conhecer a viabilidade da implementação de sistemas híbridos de geração de energia elétrica (SHGEEE) em edifícios, utilizando energia eólica e solar fotovoltaica. A metodologia para a análise técnica consistiu em obter o consumo de energia elétrica de edifícios residenciais de baixa, média e alta renda no Brasil, para assim com base nos recursos eólicos e solares de Fortaleza (CE) e Lagoa Santa (MG), realizar o balanço energético anual e desta forma dimensionar os SHGEE para seis cenários estudados. Baseado nos resultados técnicos, a metodologia econômica analisou a viabilidade financeira de implementar no Brasil os seis SHGEE dimensionados utilizando engenharia econômica para conhecer o investimento dos projetos, os custos da energia elétrica gerada pelas plantas híbridas e o período de retorno do investimento. A análise ambiental fundamentou-se em determinar a quantidade de dióxido de carbono economizado e a eficiência ecológica de cada cenário estudado considerando as fontes de energia da rede elétrica. Os resultados obtidos mostraram que os SHGEE são capazes de fornecer a eletricidade para as cargas do edifício. Os períodos de retorno do investimento dos seis SHGEE dimensionados se encontram dentro da vida útil das plantas. Em termos ambientais, as tecnologias utilizadas nos SHGEE não são totalmente não poluentes, no entanto, comparando com outras fontes de energia, estas têm baixo impacto ambiental. Conclui-se, que as aplicações de energia renováveis para edifícios são viáveis técnica, econômica e ambientalmente no Brasil. / Nowadays, governments around the world are worried about the effects of economies, industries and environment policies, making them to create regulations to encourage the use of less polluting technologies. In Brazil, the National Electric Energy Agency (ANEEL) is the federal entity to promote the implementation of renewable sources for generating electricity. ANEEL Resolution No. 482/2012 allows end users to install renewable energy sources to produce electricity for their electrical charges, increasing the percentage of alternative energy in the national energy matrix, in addition of renewable projects of large scale. In this work was made a study to know the feasibility of implementing hybrid electricity generation systems SHGEE in buildings, using wind power and solar photovoltaic energy. The methodology for the technical analysis consisted in obtaining the electricity consumption of a low, medium and high income residential building in Brazil, thus based on wind and solar resources in Fortaleza (Ceara State) and Lagoa Santa (Minas Gerais State), performing annual energy balance for dimensioning SHGEE for six scenarios studied. Considering the technical results, the economic methodology analyzed the financial feasibility of implementing in Brazil six SHGEE sized applying economic engineering and determining the project investments, the costs of electricity generated by hybrid plants and the payback period of the investment. In the environmental analysis determined the amount of carbon dioxide saved and the ecological efficiency of each scenario studied considering the sources of utility grid. The results showed that SHGEE are capable of supplying electricity to loads of the building. It is not generated electricity in all months of the year, however, with the normativity, it compensates with the months of surplus production of electricity. The return period of the investment of the six scaled SHGEE are within the lifetime of the plants. In environmental terms, the technology used in SHGEE are not completely non-polluting, nevertheless, compared with other energy sources, they have low environmental impact. In general, renewable energy applications for buildings are feasible technically, economically and environmentally in Brazil.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-19T19:08:59Z No. of bitstreams: 1 filipecaixeiromattos.pdf: 2641141 bytes, checksum: 014bbdead0d71ad1d9852cb7403b3439 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-20T12:46:42Z (GMT) No. of bitstreams: 1 filipecaixeiromattos.pdf: 2641141 bytes, checksum: 014bbdead0d71ad1d9852cb7403b3439 (MD5) / Made available in DSpace on 2017-04-20T12:46:42Z (GMT). No. of bitstreams: 1 filipecaixeiromattos.pdf: 2641141 bytes, checksum: 014bbdead0d71ad1d9852cb7403b3439 (MD5) Previous issue date: 2011-09-02 / Esta dissertação apresenta uma contribuição ao estudo de um inversor de tensão monofásico (VSI – Voltage Source Inverter), com saída em corrente, aplicado ao processamento de energia em sistemas solares fotovoltaicos (PV) monofásicos conectados à rede elétrica de distribuição. Através do controle por corrente média, é possível em um único estágio de processamento de energia rastrear o ponto de máxima potência do arranjo fotovoltaico e injetar na rede elétrica uma corrente com baixa distorção harmônica total (THD) e em fase com a tensão da rede CA. Para implementação do controle do sistema é utilizado o circuito integrado UC3854, da Texas Instruments, componente analógico de baixo custo e com funções típicas de correção de fator de potência de fontes de alimentação. Equações de análise e projeto, resultados de simulação e informações experimentais, obtidas de um protótipo de 720W, são incluídos neste material. / This dissertation presents a contribution to the study of a single-phase voltage inverter (VSI – Voltage Source Inverter), with current output, applied to the processing of photovoltaic (PV) solar power connected to single-phase electric distribution network. By controlling the average current, it is possible, in a single stage of power processing, to track the maximum power point of PV array and inject into the grid a current with low total harmonic distortion (THD) and in phase with the AC mains voltage. To implement the control system it is used a low cost Texas Instruments' analog integrated circuit UC3854, which includes a power factor correction typical function. Equations concerning analysis and design steps, simulation results and experimental data obtained from a 720W prototype are included in this document.

A hybrid photovoltaic/thermal (PVT) collector enables simultaneous electricity and heat production from a single solar module. Integrating PVT collectors with a ground source heat pump (GSHP) improves the seasonal performance of the heating system and prevents from temperature degradation of the ground. However, the integration of PVT and GSHP requires more research, for example, to discover the optimal characteristics of a PVT collector for low operating temperatures and varying weather conditions. Thus, the thermal performance of two commercial unglazed flat-plate PVT collectors was experimentally characterized during low-temperature operation and under dynamic outdoor conditions, including various solar irradiance levels and working fluid flow rates as well as frost formation and condensation on the absorber surface. The thermal performance coefficients were obtained from a simplified version of the ISO 9806:2017 standard steady-state model for solar thermal collectors and used as performance indicators for the tested collectors and for comparison with other PVT collectors found in the literature. During nighttime operation, the PVT collector with a box-channel absorber and the one with a sheet-and-tube absorber have a similar thermal performance, shown as almost the same heat loss coefficients. The effect of flow rate on the heat output of the collectors appears to be negligible when there is no solar irradiance. During humid nights, the heat gains from frost formation and/or condensation on the absorber surface can double the nighttime heat production of the collectors when compared to a dry night with no frost formation or condensation. As the irradiance increases, the box-channel collector starts to outperform the sheet-and-tube collector due to a more effective cooling of the PV module by the box-channel absorber design, which is shown as a higher zero-loss efficiency. The flow rate dependence of the heat output is increased with an increasing irradiance, higher flow rates leading to higher heat outputs. According to the yearly simulations, both tested collectors provide a higher annual heat output under Stockholm weather conditions than the other box-channel and sheet-and-tube collectors available in the Solar Keymark database, when the annual mean fluid temperature is below 7 °C. However, the fin-tube collectors designed for low-temperature heat pump integration outperform the tested collectors on annual basis with mean fluid temperatures below 10 °C. / En solhybrid (PVT) möjliggör samtidig el- och värmeproduktion från en enda solpanel. Att integrera solhybrider med en bergvärmepump förbättrar värmesystemets säsongsprestanda, förhindrar temperatur-nedgång i marken och utgör ett lovande alternativ till luftvärmepumpar. Integrationen av sol-PVT och bergvärmepumpar kräver dock mer forskning, till exempel för att upptäcka de optimala egenskaperna hos en PVT-kollektor, när driftstemperaturerna är låga och väderförhållandena varierar. Därav karakteriserades experimentellt den termiska prestandan hos två kommersiella oglasade PVT-kollektorer under drift vid låg temperatur och under dynamiska utomhusförhållanden, inklusive olika solinstrålningsnivåer och flödes-hastigheter samt frostbildning och kondensation på värmeväxlarens yta. De termiska prestandakoefficienter erhölls från en förenklad version av ISO 9806:2017-standardmodellen för stationärt tillstånd för solfångare och användes som prestandaindikatorer för de testade kollektorerna och för jämförelse med andra PVT-kollektorer som finns i litteraturen. Vid nattdrift har den första PVT-kollektorn med en ”box-channel”-värmeväxlare och den andra kollektorn med en ”sheet-and-tube”-värmeväxlare en liknande termisk prestanda vilket visas av nästan samma värme-förlustkoefficienter. Effekten av massflödet på kollektorernas värmeeffekt verkar vara försumbar, när det finns ingen solinstrålning. Under fuktiga nätter kan värmevinsterna från frostbildning och/eller kondens på värmeväxlarens yta fördubbla kollektorernas värmeproduktion på nattetid jämfört med en torr natt utan frostbildning eller kondens. När instrålningen ökar, börjar ”box-channel”-kollektorn överträffa ”sheet-and-tube”-kollektorn på grund av en mer effektiv kylning av PV-modulen genom den ”box-channel”-värme-växlaren, vilket visas som en högre nollförlusteffektivitet. Värmeeffektens beroende av flödeshastigheten ökar med en ökande solinstrålning: högre flödeshastigheter leder till högre värmeeffekt. Enligt de årliga simuleringarna har de båda testade kollektorerna en högre årlig värmeproduktion under Stockholms väderförhållanden än de andra ”box-channel”- och ”sheet-and-tube”-PVT-kollektorerna, tillgängliga i Solar Keymark -databasen, när den årliga genomsnittliga kylvätsketemperaturen är under 7 °C. Kollektorerna med en ”fin-tube”-värmeväxlare, som är utformade för integration av lågtemperaturvärmepumpar, överträffar dock de testade kollektorerna på årsbasis med genomsnittliga kylvätsketemperaturer under 10 °C.

As energy prices keep increasing, energy efficiency measures have come to the spotlight, especially in the residential sector. In this context, energy audits appear as powerful tools in order to assess the energy use and cost of energy of a dwelling, and identify possible energy saving measures that increase the energy efficiency and reduce costs. This work performs an energy audit of a single-family house (SFH) built in the 1970s which uses district heating, located in Gävle, Sweden. An empirical and quantitavive approach is followed, where energy data from the bills of 2022 together with on-site ventilation measurements is combined as a way to determine the energy inflows and outflows of the dwelling. Results concluded that the ventilation needs to be improved as a way to meet the Swedish building regulations. In addition, the energetic situation could be improved by means of the installation of solar photovoltaic (PV) modules to cover part of the electricity demand and solar thermal collectors to cover part of the domestic hot water demand. These measures would decrease the costs of the energy bills 4689 SEK/year at the time they would provide a source of renewable energy. The replacement of windows was also studied, concluding the payoff time to be excessively long to be accepted.

Purpose - In the pursuit of renewable energy sources, solar photovoltaic (PV) is predicted to become the single biggest global source of energy by the year of 2027, part of a trilemma involving climate change, biodiversity and food security. Agrivoltaic (AV) systems, the co-location and potential symbiosis between agricultural activities and solar PV, has thereby arisen as a potential solution for dual land-use. The research within this area is novel, and scholars agree that there is a need for the conceptualization of utility-scale AV in general, and the commercialization process of such systems in particular. Thereby, the purpose of this study is to unravel the key factors, activities and stakeholder involvement in order to assess the commercial potential of utility-scale AV. By addressing research questions: RQ1. What are the key factors for assessing the commercial potential of utility-scale AV?, RQ2. Which activities are essential to address these factors? and RQ3. Who are the key stakeholders that need to be involved in these activities?, a contingency framework for the assessment process has been developed. Method - In order to fulfill the purpose of this study utility-scale AV was approached as a Technology Innovation System (TIS) where the solar energy actor Sunna Group AB (Sunna) enabled insight to the potential industry context of utility-scale AV. Respondents were sampled within the TIS, forming the prerequisites for this multiple case study. Empirical data were collected in three phases: 1) Exploratory, 2) Semi-structured and 3) Final workshop, resulting in 3 workshops and 17 interviews, analyzed by a thematic analysis.  Findings - The thematic analysis resulted in four main themes: 1) Socio-political factors, 2) Techno-economical factors, 3) Meso activities for commercialization and 4) Macro activities for commercialization, under which seven key factors, six overarching activities and the stakeholder involvement in these activities, were revealed. These further formed a contingency framework providing an overview of how these building blocks are interlinked.  Theoretical & practical implications - The resulting framework provides an overview and synthesizes the commercialization of utility-scale AV, bridging the gap between stakeholder involvement and the key factors for assessing the commercial potential. The practical implications of this study primarily involve the solar energy sector, yet deemed to be of value to all potential stakeholders within the ecosystem of AV. Limitations & future research - The limitations of this study includes the potential exclusion of stakeholders within the data collection process due to the complex stakeholder configuration of AV, as well as the geographical constraints limiting this study to the context of Sweden. Future research is encouraged within several fields of this novel research area, predominantly including stakeholder involvement, business model configuration and how to mobilize the synergy sought in technology development between the solar energy- and agricultural sector.