Auxiliary services are vital for the operation of a substation. If a contingency affects the distribution feeder that provides energy for the auxiliary services, it could lead to the unavailability of the substation’s service. Therefore, backup systems such as diesel generators are used. Another alternative is the adoption of a microgrid with batteries and photovoltaic generation to supply substation auxiliary services during a contingency. Nevertheless, high battery costs and the intermittence of photovoltaic generation requires a careful analysis so the microgrid capacity is defined in a compromise between the investment and the unavailability reduction of auxiliary services. This paper proposes a method for the capacity sizing of a microgrid with batteries, photovoltaic generation, and bidirectional inverters to supply auxiliary services in substations under a contingency. A set of alternatives is assessed through exhaustive search and Monte Carlo simulations to cater for uncertainties of contingencies and variation of solar irradiation. An unavailability index is proposed to measure the contribution of the integrated hybrid microgrid to reduce the time that the substation is not in operation. Simulations carried out showed that the proposed method identifies the microgrid capacity with the lowest investment that satisfies a goal for the unavailability of the substation service.

Wind energy has become a trend in Brazil, particularly in the northeastern region of the country. Despite its advantages, wind power generation has been hindered by the high volatility of exogenous factors, such as weather, temperature, and air humidity, making long-term forecasting a highly challenging task. Another issue is the need for reliable solutions, especially for large-scale wind farms, as this involves integrating specific optimization tools and restricted-access datasets collected locally at the power plants. Therefore, in this paper, the problem of forecasting the energy generated at the Praia Formosa wind farm, an eco-friendly park located in the state of Ceará, Brazil, which produces around 7% of the state’s electricity, was addressed. To proceed with our data-driven analysis, publicly available data were collected from multiple Brazilian official sources, combining them into a unified database to perform exploratory data analysis and predictive modeling. Specifically, three machine-learning-based approaches were applied: Extreme Gradient Boosting, Random Forest, and Long Short-Term Memory Network, as well as feature-engineering strategies to enhance the precision of the machine intelligence models, including creating artificial features and tuning the hyperparameters. Our findings revealed that all implemented models successfully captured the energy-generation trends, patterns, and seasonality from the complex wind data. However, it was found that the LSTM-based model consistently outperformed the others, achieving a promising global MAPE of 4.55%, highlighting its accuracy in long-term wind energy forecasting. Temperature, relative humidity, and wind speed were identified as the key factors influencing electricity production, with peak generation typically occurring from August to November.

In this work investigated the possibility of applying a superficial treatment to ultra-fine calcium carbonate aiming to improve its interaction with the polymer chains of natural rubber so it does not act just as a filler. Commercial processes commonly use 40 phr of Silica as reinforcement filler. Here, we have evaluated the partial replacement of Silica by two types of calcium carbonate into hybrid natural rubber composites, untreated ultra-fine calcium carbonate and with ultra-fine calcium carbonate treated with 2% Chartwell C-515.71HR^®. We added calcium carbonate fillers to the composite mixtures (as replacements for commercial silica treated with silane) and studied their influence on the vulcanization process. According to our findings, between 25% and 75% of the silica can be replaced with treated calcium carbonate, and up to 30 parts of CaCO₃ can be combined with 100 parts of NR without compromising the properties of the polymer matrix (NR), which generates economic advantages for this industry. Treated calcium carbonate was able to link the inorganic and organic parts of the composite due to its bifunctionality; hence, it can be used as a filler to partially replace silica in hybrid NR composites.

This study investigates the recycling of ophthalmic lens waste (OLW) in the production of vulcanized natural rubber (NR) composites, aiming to promote sustainability and reduce costs. To this end, Vietnamese natural rubber and ophthalmic lens waste were used, varying the filler content from 0 to 50 phr. Rheological tests demonstrated that the addition of OLW decreases the cure time. The crosslink density, assessed through the Flory–Rehner and Mooney–Rivlin methods, exhibited an increase with the incorporation of a reinforcement. Thermal and spectroscopic analyses demonstrated the thermal stability of the composites and the absence of chemical interactions between the polymer matrix and the OLW. Mechanical tests showed that the composites exhibit satisfactory tensile and tear resistance, although the filler primarily acts as a filler rather than a structural reinforcement. Thus, the incorporation of OLW in NR composites emerges as a viable alternative for the reuse of industrial waste, fostering more sustainable and efficient practices in the polymer industry.

Esta pesquisa apresenta um estudo conceitual sobre as redes elétricas inteligentes (Smart Grid) e o gerenciamento de riscos de acordo baseado no guia Project Management Body of Knowledge (PMBOK) v. 6.0, assim como a elaboração de questionamentos acerca do gerenciamento de riscos. a metodologia aplicada foi uma survey utilizada para coleta de dados de profissionais de organizações do setor de energia elétrica que trabalham em projetos de redes elétricas inteligentes entregues ao setor privado. com a análise das respostas, concluiu-se que o planejamento do projeto pode ser considerado como uma fase crítica em relação ao gerenciamento de riscos do projeto, uma vez que pode apresentar maiores complicações caso não seja desenvolvida de forma satisfatória, prejudicando ainda o restante dos grupos de processos como a execução, o controle e monitoramento e o encerramento do projeto. além disso, as organizações em sua maioria realizam gerenciamento de riscos, mas nem sempre de forma frequente, completa e efetiva ou ainda utilizando técnicas e ferramentas altamente confiáveis e difundidas.

Objectives: This study aims to assess the potential of municipal solid waste (MSW)-derived solid bio-fuels as sustainable alternatives to fossil fuels. It focuses on evaluating their physical characteristics, calorific values, and flue gas emission profiles to determine their suitability for clean energy applications. Theoretical Framework: Grounded in the waste-to-energy paradigm, this review draws upon concepts of resource valorization, sustainable energy transition, and environmental management. It examines how transforming heterogeneous MSW streams into solid bio-fuels aligns with global efforts to reduce landfill burden and carbon emissions. Method: A systematic review of peer-reviewed literature was conducted using scientific databases. The analysis covered studies involving MSW briquettes, refuse-derived fuels (RDF), and biomass fractions such as food waste, paper, plastics, sawdust, and agricultural residues. Data were extracted and synthesized based on parameters like moisture content (MC), ash content (AC), volatile matter (VM), fixed carbon (FC), higher heating value (HHV), bulk density, and flue gas emissions including O₂, CO₂, CO, NOₓ, and hydrocarbons (HC). Results and Discussion: Results indicated considerable variability in feed-stock properties: MC ranged from 0.48% to 44.30%, AC from 0.4% to 42.6%, and HHV from 13.69 to 24.30 MJ/kg, with higher energy values observed in processed and plastic-rich mixtures. Bulk density spanned 170–1200 kg/m³, favoring densified forms for improved energy storage and handling. Emission data showed wide variation—O₂ (0–45.6%), CO₂ (0–23.97%), CO (0.001–2.55%), NOₓ (0.75–5000 ppm), and HC (up to 52.9 ppm)—with elevated levels often linked to plastic and organic content. Research Implications: The findings emphasize the need for standardized feed-stock preparation, blending strategies, and emission control technologies to ensure consistent fuel quality and environmental compliance. These measures are vital for integrating MSW-based solid bio-fuels into mainstream energy systems. Originality/Value: This review offers a comprehensive synthesis of existing data on MSW-derived solid bio-fuels, combining insights on fuel quality and emission behavior. It contributes to the body of knowledge by identifying practical pathways to optimize the performance and sustainability of MSW-based energy solutions.