• Energy Research
• 2021-2025close

Recent synergies have increased the use of forest biomass for energy purposes. In addition to high investment costs, low feed-in tariffs, and low operational efficiency, the real potential of forest biomass does not always correspond to the potential that is often claimed in studies. Instead of total forest biomass assessments, it is recommended that sustainable afforestation criteria should be introduced to obtain more reliable and environmentally sustainable scenarios. In this article, the most representative forest species in the Alto Minho region (northern Portugal) are identified, as well as the total forest area available. Based on cartography, forest inventory data, and allometric equations, the annually available usable residual forest biomass (RFB) and corresponding potential energy are estimated. Finally, to promote local forest biomass markets and most efficient thermal use of forest biomass is suggested the creation biomass logistic centres (BLCs) and second-generation biomass logistic centres (2GBLCs) are introduced as well.

The occupation of a territory combines a set of variables which affect the development of the mode by which populations have been organized throughout history. How this occupation takes place demonstrates much of a territory’s past and shows how the populations managed to make the most out of the available resources. The region of Entre-Douro-e-Minho (Northern Portugal), similarly to what happens in other regions, such as Galicia (Northern Spain), Brittany (Northern France), or Ireland, presents a type of dispersed land use, with an alternation of urban, agriculture, and forest areas. On one hand, this proximity allows urban populations to come into contact with a rural environment. On the other hand, this proximity also causes a set of problems, namely those related to rural fires, which are now enhanced by climate change, and associated phenomena, such as heatwaves and the lack of precipitation. The present work analyzes the evolution of rural fires in 1975–2019, in the municipality of Guimarães (Northern Portugal), to understand how these events have been distributed over time and evolved in a climate change scenario. Based on the results and discussion presented, it can be concluded that there is an increasing trend in the occurrence of rural fires in the territory under study, and that this can also be associated to climate change, in the form of a gradual increment in temperature, particularly in the autumn months, and a decrease in rainfall. This situation is responsible for the increment of the risk caused by the proximity of the populations to forest and agricultural areas because rural fires can jeopardize the safety of people and goods.

One of society’s major current challenges is carbon dioxide emissions and their consequences. In this context, new technologies for carbon dioxide (CO2) capture have attracted much attention. One of these is carbon capture and utilization (CCU). This work focuses on the latest trends in a holistic approach to carbon dioxide capture and utilization. Absorption, adsorption, membranes, and chemical looping are considered for CO2 capture. Each CO2 capture technology is described, and its benefits and drawbacks are discussed. For the use of carbon dioxide, various possible applications of CCU are described, starting with the utilization of carbon dioxide in agriculture and proceeding to the conversion of CO2 into fuels (catalytic processes), chemicals (photocatalytic processes), polymers, and building supplies. For decades, carbon dioxide has been used in industrial processes, such as CO2-enhanced oil recovery, the food industry, organic compound production (such as urea), water treatment, and, therefore, the production of flame retardants and coolants. There also are several new CO2-utilization technologies at various stages of development and exploitation, such as electrochemical conversion to fuels, CO2-enhanced oil recovery, and supercritical CO2. At the end of this review, future opportunities are discussed regarding machine learning (ML) and life cycle assessment (LCA).

The increasing levels of carbon dioxide (CO2) in the atmosphere have become a major environmental challenge due to their contribution to global warming. The primary drivers of the increase in atmospheric CO2 concentrations are the combustion of fossil fuels, deforestation, agricultural practices, or the production of cement, which play a significant role in the increase of CO2 concentration in the atmosphere. However, efforts are being made to mitigate the negative effects of CO2 emissions, including carbon capture and storage (CCS) technologies that aim to capture CO2 from industrial processes and store it in underground geological formations. Methane, another potent greenhouse gas, is another major contributor to climate change and is mainly produced by agricultural activities such as livestock farming and rice cultivation. To address this, sustainable agricultural practices, such as reducing meat consumption and adopting climate-smart farming techniques, are crucial. Ultimately, a sustainable future can be secured for the planet and future generations by implementing effective measures, such as the use of sustainable energy sources, improvements in energy efficiency, responsible land use practices, and reducing the emissions of both CO2 and methane.

Sustainability is under threat due to inefficient waste management. In the industrial sector, mechanisms such as value chains and producer obligations have advanced circular economy practices. However, in the agroforestry sector, open burning of waste remains prevalent, resulting in resource loss and heightened fire risks. This scenario jeopardizes the environmental, social, and economic pillars of sustainability, underscoring the need for legal frameworks to ensure waste recovery. This study proposes a regulatory framework to enhance the circular economy in agroforestry waste management. A benchmarking analysis was conducted to examine waste recovery systems where circular economy principles are successfully implemented. Insights from these systems were integrated with an in-depth assessment of the agroforestry biomass recovery chain to develop actionable regulatory measures. The proposed framework includes measures such as mandatory delivery of biomass, creation of aggregation centers, and incentives for biomass recovery. These measures are tailored to reduce fire risks, improve resource efficiency, and align stakeholders’ practices with sustainability goals. Visual tools, including comparative tables and diagrams, illustrate the framework’s impact. The study highlights the potential of regulatory interventions to promote agroforestry waste recovery, supporting sustainable development. Future work should focus on pilot implementations to validate the framework’s effectiveness in real-world scenarios.

One of the main causes of biodiversity loss in the world is the uncontrolled expansion of invasive plants. According to the edaphoclimatic conditions of each region, plants acquire different invasion behaviors. Thus, to better understand the expansion of invasive plants with radial growth, it is proposed to use two equations, the Annual Linear Increment (ALI) and the Annual Invasiveness Rate (AIR). These equations are applied using spatiotemporal data obtained from the analysis of orthophotomaps referring populations of Acacia dealbata Link. in areas located in Serra da Estrela, Portugal. As a result, the area occupied by this species in the parish of Cabeça was evaluated and a 20-year projection was carried out. The data produced by these equations contributed to improving the knowledge about the invasion behavior of exotic species in a rigorous and detailed way according to local ecological conditions. This study may serve as the basis for the application of other similar situations concerning invasive species in other territories, to improve the efficiency of future projections for these species. Local technical and scientific knowledge will contribute to improving spatial and management planning, enabling a better adequacy and effectiveness of the control measures to be adopted.

Evaluating Global Warming Potential (GWP) in waste management scenarios is crucial, especially in light of the escalating global concern for climate change and the pivotal role that waste management plays in mitigating this crisis. This research examines the GWP of three distinct waste management scenarios, each with a unique approach: (1) open burning, a method involving direct combustion with a GWP of 1600.1 kg·CO2eq, chiefly attributed to direct emissions without any mitigation tactics; (2) energy recovery, which capitalizes on converting waste into energy, yielding a GWP of 1255.4 kg·CO2eq, the reduction resulting primarily from avoided heat production; and (3) pyrolysis, an advanced thermal decomposition process that remarkably registers a negative GWP of −1595.1 kg·CO2eq, mainly credited to the carbon sequestration capacity of biochar production and optimal energy conversion efficiency. These outcomes emphasize the ecological merits of waste management approaches that produce lower, or even better, negative GWP values. In particular, pyrolysis emerges as a powerful way of transforming waste management into a potential carbon sink, proving crucial for climate change counteraction. Nevertheless, for effective real-world deployment, the study highlights the importance of addressing technical, economic, and societal challenges, underscoring the need for holistic, interdisciplinary research.

Citizens’ attitudes and beliefs towards climate change are decisive in the adoption of mitigating measures. Limiting the use of energy in the context of climate change can be one of the mitigation measures, and therefore, understanding the position of the citizens towards it is important. With this aim, we used data from the 10th European Social Survey to relate the European citizens’ beliefs and attitudes on limiting the use of energy to tackle climate change. We have used variables related to demography and individuals’ perception of society and its policies. Statistical models were successfully fitted to data. Individuals with higher levels of trust in scientists have a higher degree of satisfaction with the national economies, are more worried about climate change and are more capable of assuming self-responsibility in climate change mitigation. These individuals have higher probabilities of believing that climate change mitigation could be achieved by limiting the use of energy. The EU citizens are, however, very skeptical in relation to the probability of many other citizens adopting measures to limit the use of energy.