• Energy Research
• 2025-2025close
• PT close

Portugal faces water scarcity challenges, yet studies on per-household water consumption are limited. This study aims to address this gap by employing cluster analyses to assess how population trajectories, a previously overlooked aspect, and the regional location influence per-household monthly water consumption across 122 municipalities. Findings highlight higher consumption in the South despite lower prices. Municipalities experiencing population growth and those with long-term population declines show higher per-household water consumption but lower prices. Interestingly, while higher prices correlate with lower consumption, southern municipalities show increased prices without reduced consumption. Clustering reveals slight changes in consumption patterns from 2011 to 2020.

Abstract The lignocellulosic biomass (LCB) is an attractive, sustainable, and environmentally friendly alternative to fossil sources to produce biofuel, biomaterials, and biochemicals. However, its recalcitrant and heterogenous structure challenges its biodegradation and valorization. The gut microbiome of soil invertebrate species has emerged as a rich source of LCB-degrading bacteria and enzymes in terrestrial ecosystems. The primary objective of this investigation was to identify the bacterial communities within the Porcellio dilatatus gut (Crustacea: Isopods), to obtain enriched cultures, and to identify bacterial isolates with LCB-degrading activity. A total of 112 enriched cultures were screened, all exhibiting xylanolytic activity. Among them, 94 displayed cellulolytic activity, 30 showed chitinolytic activity, and 21 demonstrated ligninolytic activity. Four enriched cultures were selected, and 128 bacteria with cellulolytic, xylanolytic, chitinolytic, or ligninolytic activity were isolated and taxonomically classified. The obtained results reinforce the potential of bacterial communities within the digestive tract of soil invertebrates as a valuable source of lignocellulose-degrading microorganisms. Thirty-one isolates underwent in-depth enzymatic characterization, and five were selected and functionally evaluated. An artificial bacterial consortium was constructed to assess the potential benefits of using consortia to achieve enhanced LCB degradation. The positive results of this proof-of-concept artificial consortium (PdG-AC) can be used in future applications and is a valuable tool for enzymatic and microbial consortia engineering by, e.g., changing growth conditions for enhanced LCB-degrading abilities. Key points • The gut microbiome of Porcellio dilatatus was characterized. • Porcellio dilatatus gut hosts many lignocellulose-degrading bacteria. • Developed an artificial bacterial consortium for lignocellulose degradation.

This work explores the effectiveness of explainable artificial intelligence in mapping solar photovoltaic power outputs based on weather data, focusing on short-term mappings. We analyzed the impact values provided by the Shapley additive explanation method when applied to two algorithms designed for tabular data—XGBoost and TabNet—and conducted a comprehensive evaluation of the overall model and across seasons. Our findings revealed that the impact of selected features remained relatively consistent throughout the year, underscoring their uniformity across seasons. Additionally, we propose a feature selection methodology utilizing the explanation values to produce more efficient models, by reducing data requirements while maintaining performance within a threshold of the original model. The effectiveness of the proposed methodology was demonstrated through its application to a residential dataset in Madeira, Portugal, augmented with weather data sourced from SolCast.

Portugal is confronting a challenging position in Europe regarding energy poverty. It is consistently placed as the worst-ranked European country in various energy poverty indicators. The situation has now reached a severe point and requires urgent, targeted, and refined action in order to be effective and succeed. This internship report provides new insights for policy reformulation of existing programs designed to alleviate energy poverty and for the creation of new programs. These national programs are then dissected to examine two districts representing distinct scenarios: Lisbon, a mainly urban region, and Bragança, which is predominantly characterized as rural. The investigation used a quantitative approach, by cross-analyzing data from the energy certificates issued by ADENE – Portuguese Energy Agency – with data from the above-mentioned programs. This resulted in essential revelations regarding their possible improvement and refinement, taking into account the intrinsic characteristics of each district. The results showed an urgent need to differentiate the financing and the measures of these programs according to each type of district instead of using a national standard “one-size-fits-all” solution. This is especially relevant, as the impact of these measures produces a significantly bigger impact in rural areas than in urban regions, as their needs and challenges are very distinct. The report emphasizes the need to adapt national strategies to regional contexts, this way effectively addressing the nuanced realities of energy poverty across diverse geographical contexts. Portugal enfrenta uma posição preocupante no contexto europeu em relação à pobreza energética. É classificado como o pior país europeu em vários indicadores de pobreza energética. A situação tem vindo a atingir um nível severo e requer ação urgente, direcionada e diferenciada para ser eficaz e ter sucesso. Este relatório de estágio fornece novas ideias para a reformulação de políticas dos programas existentes projetados para combater a pobreza energética e para a criação de novos programas. Tais programas nacionais são, de seguida, examinados do ponto de vista de dois distritos que representam cenários distintos: Lisboa, uma região principalmente urbana, e Bragança, que é caracterizada como predominantemente rural. Para tal, os dados dos certificados de energia emitidos pela ADENE – Agência para a Energia – foram analisados em conjunto com os dados dos programas acima mencionados. Tal análise resultou em conclusões essenciais sobre possíveis melhorias e refinamento dos programas, tendo em consideração as características intrínsecas de cada distrito. Os resultados mostram a necessidade de diferenciar o financiamento e as medidas desses programas de acordo com o tipo de distrito, em vez de usar uma solução nacional “única”. Isto é especialmente relevante, uma vez que o impacto dessas medidas produz um efeito significativamente maior em áreas rurais do que em regiões urbanas, sendo que as suas necessidades e desafios que enfrentam são muito diferentes. O relatório enfatiza a necessidade de adaptar as estratégias nacionais aos contextos regionais, abordando assim efetivamente as nuances das realidades da pobreza energética em diversos contextos geográficos. info:eu-repo/semantics/publishedVersion

A falta de postos de carregamento em prédios habitacionais e moradias, aliada ao crescimento dos veículos elétricos, exige repensar as estruturas de carregamento. Estas podem ser compostas por fontes renováveis, permitindo o carregamento de vários veículos elétricos com menor dependência da rede elétrica. Neste trabalho desenvolveu-se um sistema de carregamento de veículos elétricos com energia solar fotovoltaica e algoritmos de gestão de energia, possibilitando o carregamento tanto com energia dos painéis fotovoltaicos quanto da rede elétrica. A escolha dos componentes e algoritmos foi baseada numa revisão bibliográfica, indicando que o sistema deve incluir um conversor DC/AC para conectar os painéis à rede elétrica e carregadores de veículos elétricos, compostos por um conversor AC/DC e um conversor DC/DC redutor. Para os algoritmos desenvolvidas três soluções de algoritmos: o Power Sharing, que divide a potência dos painéis entre os veículos; um que prioriza os veículos com menor estado de carga (SOC); e outro que distribui a potência conforme o tempo de carregamento e o SOC. Aplicou-se o sistema de carregamento desenvolvido ao software de simulação Matlab, começando por testar individualmente os controlos de corrente e tensão de cada um dos conversores e do controlo MPPT aplicado ao conversor DC/AC, posteriormente testou-se o sistema de carregamento completo para observar o comportamento do mesmo em regime transitório e em regime permanente. A simulação mostrou que o algoritmo Power Sharing fornece mais energia aos veículos, aumentando o consumo da rede elétrica quando a radiação solar é baixa, permitindo atingir um maior SOC. O algoritmo que prioriza veículos com menor SOC consome menos energia da rede, resultando num SOC menor comparado aos outros algoritmos. Concluiu-se que, para adotar este sistema na prática, é imperativo instalar uma potência fotovoltaica de 7,4 kW por cada carregador de veículo elétrico. The lack of charging stations in residential buildings and houses, coupled with the growth of electric vehicles, requires rethinking charging structures. These can be composed of renewable sources, allowing the charging of multiple electric vehicles with less dependence on the electrical grid. In this work, a system for charging electric vehicles with photovoltaic solar energy and energy management algorithms was developed, enabling charging with both photovoltaic panel energy and grid electricity. The choice of components and algorithms was based on a literature review, indicating that the system should include a DC/AC converter to connect the panels to the electrical grid and electric vehicle chargers, consisting of an AC/DC converter and a step-down DC/DC converter. Three algorithm solutions were developed: Power Sharing, which divides the power from the panels among the vehicles; one that prioritises vehicles with a lower state of charge (SOC); and another that distributes power according to charging time and SOC. The developed charging system was applied to Matlab simulation software, starting with individual tests of the current and voltage controls of each converter and the MPPT control applied to the DC/AC converter. Subsequently, the complete charging system was tested to observe its behaviour in both transient and steady-state regimes. The simulation showed that the Power Sharing algorithm provides more energy to the vehicles, increasing grid consumption when solar radiation is low, allowing for a higher SOC. The algorithm that prioritises vehicles with a lower SOC consumes less grid energy, resulting in a lower SOC compared to the other algorithms. It was concluded that, to adopt this system in practice, it is imperative to install a photovoltaic power of 7.4 kW per electric vehicle charger.

Wave energy converters (WECs) have significant potential for renewable energy generation, but early-stage design processes often require lengthy simulations. This study focuses on the pre-design selection of the rated power for a heaving point-absorber WEC. Addressing the gap in simplified methodologies, this study evaluates the wave energy resource, selects operational sea-states, and assesses device performance using time-domain simulations and linear potential flow theory. The results revealed that a WEC rated at 87% below peak power can capture 91% of the total available energy, achieving a balance between energy efficiency and cost-effectiveness. Furthermore, a simplified method to estimate rated power based on a constant ratio between mean and RMS power is proposed, offering significant potential for early-stage design applications. Future work should validate this approach across diverse WEC types and wave climates.

This study investigates the co-treatment of leachate and domestic sewage in municipal wastewater treatment plants using aerobic granular sludge (AGS) systems, focusing on granule formation, system stability, and resource production in two units (R1 and R2). In R2, solids retention time (SRT) was controlled between 10 and 25 days, while R1 maintained approximately 9 days. The results show that low leachate proportions (5 %) did not affect system performance or stability. However, increasing the leachate to 10 % reduced the structural stability of extracellular polymeric substances (EPS), leading to a significant decrease in alginate-like exopolysaccharides (ALE) production in R1 (216 mgALE/gVSS) and R2 (125 mgALE/gVSS). Principal component analysis revealed that SRT was crucial for optimizing biopolymer synthesis. Furthermore, SRT control in R2 improved filamentous control, biomass retention, and total nitrogen removal. Thus, selective biomass discharge is essential for maintaining granule stability, enhancing treatment efficiency, and supporting resource production.