https://repositorio.ufpb.br/jspui/handle/tede/7763 PPGER Thu, 30 Apr 2026 18:27:24 GMT 2026-04-30T18:27:24Z http://repositorio.ufpb.br:443/jspui/retrieve/37076/ https://repositorio.ufpb.br/jspui/handle/tede/7763 https://repositorio.ufpb.br/jspui/handle/123456789/37358 Título: Gases de efeito estufa associados às operações de uma cooperativa de materiais recicláveis Autor(es): Oliveira, Murilo dos Santos Orientador: Carvalho, Monica Abstract: Recyclable material cooperatives play a crucial role in promoting recyclingandmaterial circularity, generating resource savings and environmental benefits; however, theiractivities also result in greenhouse gas (GHG) emissions. These emissions stemfromtheprocessing and transportation of recyclable materials. Life Cycle Assessment (LCA) isavital methodology for identifying the environmental impacts of different waste treatment methods, guiding decisions on more sustainable technologies and policies. Thus, theoverall objective of this study is to assess the GHG emissions associated with the wastecollection process of the Itamare recycling cooperative, located in the municipalityofItabaiana (Paraíba – Brazil), and to investigate strategies for their mitigation. Toachievethis, three specific objectives were defined. The first involves a systematic literature reviewthat combines bibliometric analysis and content analysis, focusing on recyclingcooperatives and LCA. This stage provided a broader understanding of the current stateofthe art in both areas. The results showed that, within a set of 54 articles addressingrecycling cooperatives, only 12% discussed the LCA methodology, highlightingadeveloping field and a possible lack of awareness regarding the importance of this methodfor the subject under study. This review also enabled the selection of articles that providedthe necessary foundation for the analyses required in the design of the study. In the secondstage, GHG emissions (carbon footprint) associated with the Itamare recycling cooperativewere quantified. For this purpose, the LCA methodology was applied, consideringtheprocesses of collection, processing, and transportation of waste destined for recyclingcompanies. It was found that, from a total of 194.98 t CO₂-eq emitted monthly, 99.9%wereassociated with the collection of 150 tons of assorted waste and the transportationof 40tons of plastic waste using a diesel-powered vehicle. This portion accounted for over 99%of the GHG emissions, highlighting transportation as the main critical point. Finally, inthethird stage, technological alternatives with the potential to reduce these emissions wereinvestigated. Initially, the replacement of regular diesel with S-10 diesel was considered, followed by blends of biodiesel (at 20%, 25%, and 100% proportions). The possibilityofreplacing the cooperative’s truck with an electric vehicle was also considered. The resultsshowed that using 20% and 25% biodiesel could reduce GHG emissions by up to3.06%(715.04 t CO₂-eq/year), provided that compatible vehicles are used. With pure biodiesel, the reduction could reach 29.99%, also depending on vehicle adaptation. The data collectedmay guide other cooperatives and promote sustainable practices in the sector, reinforcingthe importance of integrating science, operations, and public policy in the transitiontoalow-carbon economy. Editor: Universidade Federal da Paraíba Tipo: Dissertação Tue, 29 Jul 2025 00:00:00 GMT https://repositorio.ufpb.br/jspui/handle/123456789/37358 2025-07-29T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/37290 Título: Amortização do passivo ambiental de sistemas solares fotovoltaicos: estudo de caso no edifício CEAR-UFPB Autor(es): Araújo, Ana Paula Freire de Orientador: Carvalho, Monica Abstract: The increase in electricity generation through renewable sources has been a global strategy to reduce greenhouse gas (GHG) emissions from the energy generation sector, thus contributing to mitigating climate change. This study aimed to evaluate the environmental impacts of photovoltaic systems, focusing on the calculation of environmental payback time and the reduction of GHG emissions. The Life Cycle Assessment (LCA) methodology was used, which allowed for quantifying the environmental impacts throughout the life cycle of photovoltaic systems. The study was structured into three articles: the first conducted a bibliometric review of the diffusion of LCA in photovoltaic systems, highlighting the need for greater participation from Latin American and African countries in research on the topic. The second article calculated the life cycle inventory of the original photovoltaic system for a university building and quantified the GHG emissions. In the third article, an update to the photovoltaic system was proposed, using more modern modules. The results showed that, by adopting more efficient models, energy production increased by 39.40% and 106.67% in Scenario 1 (system power) and Scenario 2 (total area utilization), respectively. Additionally, the choice of more efficient modules contributed to the reduction of GHG emissions, decreasing the environmental payback time. In Scenario 0, which used the original system, GHG emissions were 182,927 kg CO2-eq, with 266,531.48 kg CO2-eq of emissions avoided, and the environmental payback time was 13 years, 3 months, and 29 days, with a total production of 2,539,126 kWh. In Scenario 1, which considered the system's power, GHG emissions were 89,406 kg CO2-eq, with 407,572.54 kg CO2-eq of emissions avoided, and the payback time was reduced to 5 years and 14 days, with a production of 3,539,646.71 kWh. In Scenario 2, which utilized the total available area, GHG emissions were 141,006 kg CO2-eq, with 593,644.25 kg CO2-eq of emissions avoided, and the payback time was 5 years, 5 months, and 13 days, with a total production of 5,247,501.79 kWh. These results highlight the potential of photovoltaic systems to mitigate the environmental impacts of electricity generation, especially when using more efficient technologies, which not only increase energy production but also significantly reduce GHG emissions and environmental payback time. Editor: Universidade Federal da Paraíba Tipo: Dissertação Thu, 17 Apr 2025 00:00:00 GMT https://repositorio.ufpb.br/jspui/handle/123456789/37290 2025-04-17T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/37124 Título: Emissões de gases de efeito estufa no processamento da mandioca: um estudo de mitigação com base em avaliação de ciclo de vida Autor(es): Bezerra, Julio Cesar Sales Orientador: Abrahao, Raphael Abstract: Cassava (Manihot esculenta Crantz) plays a key role in ensuring food and economic security for small farmers in tropical countries. In this context, the present study aimed to detail the production process of cassava flour, focusing on the quantification of greenhouse gas (GHG) emissions through Life Cycle Assessment (LCA), as well as on the identification of effective strategies to reduce these environmental impacts. To achieve this goal, the study was guided by three specific objectives. The first was to conduct a bibliometric review on the application of LCA to the cassava production chain and its processing into flour. The analysis revealed that only 118 publications were produced between 1981 and 2023 on cassava-related topics, of which only 10 directly addressed the LCA of the cassava production process, indicating a significant gap in scientific knowledge. The second specific objective referred to the execution of the LCA of the cassava flour production process, covering the stages of planting, harvesting, and processing. Two cassava flour mills, referred to as CF-I and CF-II, were analyzed. The LCA results indicated that the emissions associated with the annual production of 2,600 kg of cassava flour were 2,449.28 kg CO2-eq/year for CF-I and 1,027.03 kg CO2-eq/year for CF-II. These differences were due to the type of fossil fuel used for transporting the roots and the type of oven used in the roasting process, which directly affects the amount of firewood consumed. These stages were identified as the main sources of GHG emissions in the two units analyzed. Finally, the third specific objective was related to mitigation strategies. Replacing the fuel used in transportation and adopting a more energy-efficient oven resulted in reductions of 357.49 kg CO2-eq/year in root transportation and 1,672.32 kg CO2-eq/year in the roasting process, corresponding to 90.3% and 60.0% of the original emissions, respectively. The results demonstrate that implementing sustainable practices, even in small-scale units, can significantly reduce emissions without compromising productivity. Editor: Universidade Federal da Paraíba Tipo: Dissertação Wed, 30 Jul 2025 00:00:00 GMT https://repositorio.ufpb.br/jspui/handle/123456789/37124 2025-07-30T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/36799 Título: Modelagem e desempenho de recursos baseados em inversores seguidores de rede diante de curtos-circuitos na linha de interconexão Autor(es): Martins, Pedro Henrique de Morais Orientador: Lopes, Felipe Vigolvino Abstract: This work evaluates the influence of different phase-locked loop (PLL) structures on the response of grid-following inverter-based resources (IBRs) under faults on the interconnection line, considering the voltage support requirements established by the Brazilian Transmission System Operator (TSO). A representative 100 MVA wind power plant was modeled in four configurations: 50 units of 2 MVA, 20 of 5 MVA, 5 of 20 MVA, and an equivalent aggregated model. Three PLL topologies were analyzed — Synchronous Reference Frame (SRF), Quadrature Signal Generator with Second-Order Generalized Integrator (QSG-SOGI), and Multiple SRF (MSRF) — under three-phase, two-phase, and single-phase grounded faults applied at the midpoint of the interconnection line, with resistances defined according to technical standards. The results show that PLL performance directly affects the IBR response to faults, with distinct behaviors depending on the fault type, due to the nonlinear nature of the controllers and the presence of harmonics and waveform distortions. The SRF-PLL showed greater sensitivity to these distortions, resulting in pronounced oscillations in the estimated voltage, abrupt variations in reactive power injection, and higher harmonic content in the injected currents, especially during two-phase faults. In contrast, QSG-SOGI and MSRF PLLs demonstrated greater robustness, providing more stable estimates and more reliable control system behavior. The short-time window analysis — particularly within the first 20 ms after the fault — revealed that estimation errors in the SRF-PLL can compromise the performance of protection functions, highlighting the importance of knowing the PLL topology used. Simulations also indicated that equivalent IBR models with the same nominal power present similar transient responses when using the same PLL structure, regardless of the number or size of the units. This confirms the effectiveness of using aggregated models or units with higher ratings as a strategy to reduce computational burden without compromising the accuracy of dynamic simulations during fault transients. Based on this conclusion, new fault studies were carried out, varying the fault location and grounding resistance. The three-phase fault was found to be the most critical, with more severe effects when it occurred closer to the local terminal. The two-phase and single-phase faults exhibited a moderate increase in current as the fault moved closer to the terminal, and the single-phase fault showed more pronounced oscillatory behavior. It is concluded that the appropriate selection of the PLL topology, together with representative modeling of IBRs, is essential to ensure compliance with grid codes, protection reliability, and the operational stability of systems with high renewable penetration. Editor: Universidade Federal da Paraíba Tipo: Dissertação Wed, 30 Jul 2025 00:00:00 GMT https://repositorio.ufpb.br/jspui/handle/123456789/36799 2025-07-30T00:00:00Z