In recent years, distributed generation (DG) has expanded substantially in Brazil, driven by technological advances, declining installation costs, and regulatory measures that have created favorable conditions for its integration into the electricity sector. Despite its benefits, this expansion has introduced technical and regulatory challenges for distribution networks. Therefore, this study examines the evolution of the Brazilian DG regulatory framework, the growth of micro- and mini-distributed generation (MMDG) from 2015 to 2025, and the effects of photovoltaic DG on distribution network operation. The analysis combines a review of regulatory milestones and national energy statistics with power flow simulations performed using OpenDSS and MATLAB on a 136-bus distribution system. The simulations consider different DG penetration levels, installation locations, DG coverage, and inverter power factors. The regulatory analysis shows how Brazil's framework evolved to address grid connection requirements, electricity compensation mechanisms, and network operation. Furthermore, during the period examined, MMDG installed capacity increased from 16.5 MW in 2015 to approximately 45 GW in 2025, with photovoltaic systems accounting for 99.3% of the total. Regarding the technical impacts of DG, the simulations demonstrated that penetration levels, installation locations, DG coverage, and inverter power factors influence voltage profiles and active power losses. Distributing DG along the feeder contributed to reducing active power losses, while reactive power injection further reduced losses and voltage deviations. At 100% penetration, active power losses decreased from approximately 325 kW without DG to 26 kW with reactive power support. However, at higher penetration levels, losses increased under certain conditions, and reverse power flow occurred. These findings highlight the importance of considering network characteristics, DG allocation, and inverter operating conditions in connection assessments and distribution system planning.
O uso de sistemas ar-condicionado em vagões de passageiros representa cerca de 30% do consumo de eletricidade provida pelo gerador a diesel existente nas locomotivas. Realizar uma estimativa de carga térmica para o setor de transportes - em específico os intermunicipais - é de extrema relevância, pois permite adequar o sistema de ar-condicionado e os mecanismos de isolamento térmico, levando ao aumento do conforto dos passageiros e redução do consumo energético. O objetivo desse estudo é analisar a influência de parâmetros, tais como: o clima regional, a orientação geográfica, a estação do ano e a hora do dia sobre a carga térmica e o consumo energético do sistema de ar-condicionado de um vagão de passageiros da Estrada de Ferro Vitória a Minas (EFVM). Nesse sentido, as viagens foram simuladas considerando as dimensões e os materiais construtivos do vagão como uma edificação sujeita a diferentes orientações geográficas, horário de ocupação, atividade humana e dados climáticos, para permitir a simulação da viagem completa nos dois sentidos, ou seja, Belo Horizonte a Vitória, e vice-versa. Concluiu-se que: existe um padrão de consumo para cada sentido de viagem; a influência da orientação geográfica varia drasticamente com a estação do ano; as estações do ano apresentaram maior influência na análise isolada, além de afetar a magnitude de valores em todas as outras análises. Por fim foi testado e confirmado a redução de cerca de 10% no consumo energético ao instalar filme nas janelas.
The growing share of intermittent sources, such as solar and wind power, in the electricity mix has heightened the need for storage systems capable of mitigating fluctuations in supply and ensuring energy security. Among the available technologies, pumped-storage hydropower (PSH) plants stand out; they store energy by pumping water to an elevated reservoir, allowing it to be used later for electricity generation. However, topographical and environmental constraints can limit their implementation. In this context, this study proposed an alternative storage system based on the principles of pumped-storage hydroelectric plants, in which the upper reservoir is replaced by a pressurized reservoir. In this configuration, energy is stored through the compression of the air confined within the reservoir. The study involved mathematical modeling of the pumping and turbine stages, followed by computational simulation using the Python programming language. The results made it possible to analyze the temporal evolution of operational variables and to evaluate the efficiency of the proposed system, showing that the system, in its current configuration, exhibited lower efficiency than conventional pumped-storage hydroelectric plants. Thus, this research presents the concept of the system and establishes a foundation for future studies.
The use of soils as natural pigments in paint production has been proposed as a potentially sustainable alternative to the socioenvironmental impacts of conventional industrial paints. This study evaluated the texture and decantation behavior of soil-based paints over a 70-day period, using two soil samples collected in the municipality of Ilhéus–BA. Paints were formulated by combining processed soil with water and a commercial polyvinyl acetate (PVAc) binder, homogenized using a household blender, resulting in four samples (two per soil). Two of these samples (01 and 02), prepared with a higher water-to-soil ratio, were qualitatively assessed as excessively fluid and dissimilar to conventional paint, and were therefore excluded from the long-term monitoring; the detailed analysis was accordingly conducted on Samples 03 and 04. Combined sieve and hydrometer analysis revealed contrasting textures between the soils: Soil 1 (Vilela) presented a predominantly sandy composition (66.57% sand, 11.02% clay), whereas Soil 2 (Esperança) presented a predominantly fine-grained, clay-rich composition (71.37% total fines, 40.19% clay). Consistency tests were in line with this textural contrast: Soil 2 presented a Liquid Limit of 84.33% and a Plasticity Index of 39.72%, values considerably higher than those of Soil 1 (LL = 58.29%; PI = 25.53%), indicating that plasticity in these soils tracks their clay content. Both formulations could be manually applied to the test specimens and produced visually continuous coatings, an appearance that was maintained after 70 days of storage once remixed. These preliminary results support the potential of locally sourced soils as pigments in low-cost coatings, with homogenization before use identified as an indispensable step; a broader assessment of durability, toxicity, and environmental impact is still needed before wider sustainability claims can be made. Future studies should include mineralogical analysis (X-ray diffraction) to confirm the nature of the fine fraction, matched formulations with controlled binder content, and evaluation of stabilizing agents to optimize formulation stability.
A escassez de dados hidrológicos em pequenas bacias hidrográficas não monitoradas é um desafio significativo para a gestão sustentável dos recursos hídricos, especialmente em regiões tropicais. Este estudo avaliou a aplicabilidade dos dados de precipitação estimados pelo satélite GPM IMERG, corrigidos por Quantile Mapping, na modelagem hidrológica de uma pequena bacia hidrográfica no Brasil. O modelo IPH-II foi utilizado para simular o comportamento hidrológico da bacia, e os resultados das simulações com dados estimados foram comparados com aqueles obtidos a partir de dados observados. Os resultados demonstraram que os dados de satélite corrigidos podem produzir simulações representativas para pequenas bacias hidrográficas, especialmente no que tange às vazões médias e altas, embora eventos extremos ainda apresentem maior discrepância. A metodologia proposta mostrou-se viável para ampliar o monitoramento hidrológico em regiões com baixa densidade de estações, contribuindo para o desenvolvimento de soluções aplicáveis à gestão de pequenas bacias hidrográficas e promovendo a integração de dados estimados por satélite em modelagens práticas e acessíveis.
