Search Results (234)

Brazil possesses a large bioenergy resource, embedded in agro-industrial, livestock, and urban residues; this study quantifies its technical magnitude and associated energy value. An assessment was conducted by substrate, combining official statistics with literature-based yields and recovery factors. Biogas volumes were converted into biomethane using representative upgrading efficiencies, and thermal and electrical equivalents were derived from standard lower heating values and conversion efficiencies. Uncertainty bounds reflect the variability of feedstock yields and process performance. The national technical potential is estimated at roughly 80–85 billion Nm³/year of biogas, corresponding to ~43–45 billion Nm³/year of biomethane and around 168–174 TWh/year of electricity. Contributions are led by the sugar–energy complex (~one-third), followed by livestock and other agro-industrial residues (~one-third), while urban sanitation supplies ~8–10%. Potentials are concentrated in the Southeast, Center-West, and South, and current production represents only ~2–3% of the assessed potential. The findings indicate that realizing this potential requires targeted measure standardization for grid injection, support for pretreatment and co-digestion, access to credit, and alignment with instruments such as RenovaBio and “Metano Zero” to unlock significant methane-mitigation, air-quality, and decentralized energy-security benefits. Full article

This study investigates the role of biogas and biomethane in accelerating the decarbonization of district heating systems in Europe. A structured literature review combined with two representative case studies evaluate technological, economic, and environmental performance across different system scales. The Meppel optimization model developed for the Netherlands and the large-scale Backbone energy system modelling framework for Finland are compared to identify methodological synergies and operational insights for integrating bioenergy into heating networks. The results show that biogas-based combined heat and power systems can reduce carbon dioxide emissions by more than 70 percent compared with fossil-based alternatives and significantly improve local energy security, especially when coupled with heat pumps and thermal storage. Large-scale modelling further demonstrates that biomethane and bioenergy resources provide valuable system flexibility, facilitating sector coupling and supporting the balancing of variable renewable electricity production. This study’s main contribution is an integrated comparative assessment at two different scales (local and regional), linking operational data, modelling, and performance results to determine how biogas and biomethane can optimize the energy system in the short and long term for centralized heat supply. The findings confirm that biogas and biomethane are essential, dispatchable renewable resources capable of supporting scalable, low-carbon, and resilient district heating systems across Europe. Full article

This review examines how the integration of circular bioeconomy principles with digital technologies can drive climate change mitigation, improve resource efficiency, and facilitate sustainable biorefinery development. This highlights the urgent need to transition away from fossil fuels and introduces the bio-circular economy as a regenerative model focused on biomass valorization, reuse, recycling, and biodegradability. This study compares linear, circular, and bio-circular approaches and analyzes key policy frameworks in Europe, Latin America, and Asia linked to several UN Sustainable Development Goals. A central focus is the role of digitalization, particularly artificial intelligence (AI), the Internet of Things (IoT), and blockchain. Examples include AI-based biomass yield prediction and biorefinery optimization, IoT-enabled real-time monitoring of material and energy flows, and blockchain technology for supply chain traceability and transparency. Applications in agricultural waste valorization, bioplastics, bioenergy, and nutraceutical extraction are also discussed in this review. Sustainability tools, such as automated life-cycle assessment (LCA) and Industry 4.0 integration, are outlined. Finally, future perspectives emphasize autonomous smart biorefineries, biotechnology–nanotechnology convergence, and international collaboration supported by open data platforms. Full article

The creation of bioenergy based on the biomass wood pellet industry, which accounts for the majority of the global biomass supply, is one of the most common and important ways to utilize waste wood, wood dust, and other byproducts of wood manufacturing, known as forestry residues. Pellet production processes might greatly benefit from fast monitoring systems that may allow for at least a semi-quantitative measurement of crucial parameters such as lignin and cellulose. The determination of lignin and cellulose is complicated and time-consuming because it usually requires time-demanding and labor-intensive sample preparation. This, however, might be a crucial problem. In this context, the application of Raman spectroscopic techniques is considered a promising approach, as it enables rapid, reliable, and label-free analysis of wood pellets, providing information about the chemical composition of the biomass, specifically lignin and cellulose. The purpose of this article is to report on the application of Raman spectroscopy exemplified by the detection of the lignin/cellulose ratio. In our methodological approach, we integrated the area under the selected Raman bands to avoid a large scatter of data when only the intensities of the bands were used. Moreover, the acquired Raman spectra displayed very strong signals from both substances, which contributes to the feasibility of the analysis even with a portable instrument. This study is expected to be of assistance in situations when the monitoring of the chemical changes and the quick inspection of pellets are required in near real time, online, and in situ. Full article

In the Republic of Moldova, orchard biomass represents an important resource for the production of densified solid biofuels, with peach having the highest sustainable energy potential (33.5 ± 6.54 GJ·ha⁻¹). However, the quality of solid biofuels derived from orchard biomass is often constrained by heterogeneity in moisture content, uneven particle size distribution, and inadequate drying or blending practices along the supply chain. Optimizing the solid biofuel supply chain is therefore essential to minimize feedstock variability, ensure consistent densification quality, and reduce production costs. The aim of this study was to improve the process of producing densified solid biofuels from orchard biomass. Specifically, the study investigated how raw material moisture and particle size influence briquette density and durability, and how ternary mixtures of peach biomass, wheat straw, and sunflower residues can be optimized for enhanced energy performance. All experimental determinations were performed using validated methods and calibrated equipment. The results showed that optimal performance is achieved by shredding the biomass with 4–8 mm sieves and maintaining the moisture content between 6 and 14%, resulting in briquettes with the density of 1.00–1.05 g·cm⁻³, ash content below 3–5%, and an energy yield of 18.4–19.2 MJ·kg⁻¹. Ternary diagrams confirmed the decisive role of peach lignocellulosic residues in achieving high density, low ash content, and increased energy yield, while wheat straw and sunflower residues can be used in controlled proportions to diversify resources and reduce costs. These findings provide quantitative insights into how mixture formulation and process parameters influence the briquette quality, contributing to the optimization of solid biofuel supply chains for orchard and agricultural residues. Overall, this study demonstrates that competitive solid biofuels can be produced through careful balancing of mixture composition and optimization of technological parameters, offering practical guidelines for sustainable bioenergy development in regions with abundant orchard residues. Full article

This paper investigates how the existing pellet plant of the Energy Community of Karditsa (ESEK) can be leveraged to strengthen RESCoop operations by integrating a variety of biomass feedstocks as (i) urban residual biomass, (ii) forest residues, and (iii) alternative sources such as spent coffee grounds (SCGs). The RESCoop envisions an extended role as an Energy Service Company (ESCO) by installing and operating biomass boilers in local public buildings. The paper provides an overview of the technical and business support that was provided to the RESCoop for the development of such new business activities and aggregates the lessons learned from engaging the rural society towards sustainable bioenergy production. More specifically, the study covers the logistical aspects of the new RESCoop value chains, including availability, collection, transportation, and processing of the feedstocks along with their costs. A base case scenario investigates the feasibility of installing biomass boilers in municipal buildings through a detailed financial viability study examining capital and operational expenses, revenues, and key financial indicators. Further, the environmental and socio-economic impacts of the new RESCoop activities are evaluated in terms of CO₂ equivalent savings compared to fossil fuel solutions and new job creation, respectively. This detailed analysis highlights the potential for sustainable bioenergy integration and provides valuable insights for similar initiatives aiming to diversify and enhance sustainable energy practices in local communities. Full article

The incorporation of cattle slurry in soil in short-rotation-cycle poplar cultivations can be a win–win strategy, insofar as a main feedstock derived from local intensive dairy cattle breeding can be used as a natural fertilizer and in bioenergy produced in the same region. The circularity of this process can contribute to boosting local socio-economic value. In this context, this work involved the installation of a poplar SRC plantation with a density of 5330 trees ha⁻¹ in a 4000 m² moderately fertile flat site, which was formerly used as a vineyard. Mechanical dosages of slurry of 0, 26.6, 53.2, and 106.5 Mg ha⁻¹, designated as treatments T0, T1, T2, and T3, were applied three times per year during 2019, 2020, and 2021. The variables quantified were related to plant growth, biomass productivity and mass balances of K, P, Cu, Zn, Mg, and N, and organic matter in the whole soil, plant, and slurry system during the first rotation cycle. For treatments T0 and T1, all these seven chemical components showed positive balances in the system, with cumulative demand by soil and biomass being higher than cumulative supply by slurry. Negative balances occurred for P with T2 and T3 and for Zn with T3, so that an overall condition of nutrient saturation of the whole system was not achieved. A no-slurry application, or at most a moderate application equivalent to T1, in the second rotation cycle should therefore be prescribed to allow a nutrient equilibrium status to be achieved through internal seasonal recycling mechanisms. The biomass average productivities ranged from 6.1 to 11.8 Mg ha⁻¹ y⁻¹, peaking under treatment T2, and are within the typical values for a first rotation cycle for poplar SRCs. The biomass fuel quality was not affected by the slurry treatments. A good performance of plant total height and growth in diameter at breast height suggested that poplar trees were not stressed by the applied slurry. Only treatment T1 could assure that cattle CO₂-eq methane emissions were overall equilibrated by the carbon sequestration from poplar cultivation, with an absence of climatic-warming impacts. Treatments T2 and T3 could only partially minimize that impact, which would always exist. Globally, this site-specific analysis showed that, under moderately fertile conditions, controlled cattle slurry fertilization of poplar SRC cultivations, which would assure a long-term steady-state equilibrium, can be a viable option to contribute to decentralized production of bioenergy in rural communities. Full article

The decarbonization of hard-to-defossilize sectors, such as international maritime transport, requires innovative, and at times disruptive, energy solutions that combine efficiency, scalability, and climate benefits. Therefore, power-to-liquid (PtL) routes have stood out for their potential to use low-emission electricity for the production of synthetic fuels, via electrolytic hydrogen and CO₂ capture. However, the high energy demand inherent to these routes poses significant challenges to large-scale implementation. Moreover, PtL routes are usually at most neutral in terms of CO₂ emissions. This study evaluates, from a thermo-energetic perspective, the optimization potential of an e-methanol synthesis route through integration with a biomass oxy-fuel combustion process, making use of electrolytic oxygen as the oxidizing agent and the captured CO₂ as the carbon source. From the standpoint of a first-law thermodynamic analysis, mass and energy balances were developed considering the full oxygen supply for oxy-fuel combustion to be met through alkaline electrolysis, thus eliminating the energy penalty associated with conventional oxygen production via air separation units. The balance closure was based on a small-scale plant with a capacity of around 100 kta of methanol. In this integrated configuration, additional CO₂ surpluses beyond methanol synthesis demand can be directed to geological storage, which, when combined with bioenergy with carbon capture and storage (BECCS) strategies, may lead to net negative CO₂ emissions. The results demonstrate that electrolytic oxygen valorization is a promising pathway to enhance the efficiency and climate performance of PtL processes. Full article

Renewable energy expansion requires cost-effective strategies to integrate underutilized biomass resources into energy systems. In Australia, forest residues represent a significant but largely untapped feedstock that could contribute to a more diversified energy portfolio. This study presents an integrated geospatial and optimization decision-support model designed to minimize the total cost of forest biomass-to-bioenergy supply chains through optimal facility selection and network design. The model combined geographic information systems with mixed-integer linear programming to identify the optimal candidate facility sites based on spatial constraints, biomass availability and infrastructure proximity. These inputs then informed an optimization framework that determined the number, size, and geographical distribution of bioenergy plants. The model was applied to a case study in Queensland, Australia, evaluating two strategic scenarios: (i) a biomass-driven approach that maximizes the use of forest residues; (ii) an energydriven approach that aligns facilities with regional energy consumption patterns. Results indicated that increasing the minimum facility size reduced overall costs by capitalizing on economies of scale. Biomass collection accounted for 81%–83% of total supply chain costs (excluding capital installation), emphasizing the need for logistically efficient sourcing strategies. Furthermore, the system exhibited high sensitivity to transportation distance and biomass availability; energy demands exceeding 400 MW resulted in sharply escalating transport expenses. This study provides a scalable, data-driven framework for the strategic planning of forest-based bioenergy systems. It offers actionable insights for policymakers and industry stakeholders to support the development of robust, cost-effective, and sustainable bioenergy supply chains in Australia and other regions with similar biomass resources. Full article

In the interest of climate protection and the promotion of a sustainable economy, the European Union (EU) is pursuing a policy of transitioning from fossil fuels to renewable energies. The objective of this initiative is twofold: first, to reduce greenhouse gas (GHG) emissions, and second, to decrease the reliance on energy imports. This article utilizes publicly accessible databases and studies to assess the extent to which bioenergy (including fuels, heat, and electricity) contributes to these objectives and its long-term potential. Presently, bioenergy constitutes approximately 14% of Europe’s energy supply, with a share of 60% ranking as the foremost source of renewable energy. The evaluation of bioenergy-related GHG is hindered by the fact that the official databases do not satisfy the criteria necessary for scientific analysis. Further expansion of bioenergy should be based on European non-food biomass, as required by the current Renewable Energy Directive REDIII. Taking competing non-energy uses into account, the potential for further growth, contribution to total energy supply, and independence from imports is likely to be limited. As part of the strategic development of bioenergy, there is a considerable need for research into the use of biomass for competing energy and material use pathways, taking into account the different economic potential. To this end, the introduction of a new economic indicator of value creation intensity is proposed. Full article

This paper reviews various emerging alternative SCMs derived from minerals and biomass sources, industrial byproducts, and underutilized waste streams. The paper compiles and evaluates physicochemical properties, reaction mechanisms in cementitious systems, resource availability, supply chain dynamics, technology readiness, the impact on concrete performance, and environmental and cost factors for each candidate SCM. Specifically, the review examines wood ash from bioenergy plants, volcanic and sedimentary natural pozzolans, and construction and demolition waste. This includes recycled concrete fines, asphalt plants’ rock dust (baghouse fines), aggregate production fines, and post-consumer waste, particularly municipal solid waste incinerator ash and wastewater sludge ash. Additionally, the paper explores innovative additives such as cellulose and chitin nanomaterials and calcium–silicate–hydrate nanoseeds to address challenges of slower strength development and rheological changes. The key contribution of this review is a multifactor framework for assessing alternative SCMs, emphasizing availability, supply chain, market readiness, and environmental performance, combined with an engineering performance review. Full article

This study analyses the potential electricity output from different bio wastes using various energy conversion technologies to enhance the share of renewable energy. Furthermore, it evaluates the carbon emissions mitigated by replacing fossil fuels with bioenergy, contributing to efforts to reduce environmental pollution. The findings reveal that Egypt’s annual biomass waste (BW) could total approximately 80 million tons, with the most significant contributions from agricultural crop residues and municipal solid waste (MSW). MSW incineration and crop residue combustion were found to have the highest power generation compared to other techniques. Additionally, the anaerobic digestion of various biomass types offers the benefits of lower greenhouse gas emissions while still generating significant energy. The electricity generation from different BW sources is approximately 49.14 TWh/year. This energy can be predominantly generated through direct combustion of agricultural crop residues (66%), incineration of MSW (29%), anaerobic digestion of sewage sludge (3%), and animal waste (2%). Furthermore, the reduction in carbon emissions from substituting fossil fuels with bioenergy is estimated at up to 30.47 million tons of CO₂ annually, supporting efforts to mitigate climate change and combat global warming. Full article

Small-scale fisheries and aquaculture play a crucial role in securing food, income, and nutrition for millions, especially in the Global South. Rural small-scale aquaculture (SSA) is characterized by limited investment and technical training among farmers, diversification and dispersion of farms over large areas, reduced access to competitive markets for inputs and products, and family labor. Small-scale integrated circular aquaponic (ICAq) systems, in which systems’ component outputs are transformed into component inputs, have significant potential to increase circularity and promote economic development, especially in a rural context. We offer an integrated and comprehensive approach centered on aquaponics or aquaponic farming for small-scale aquaculture units. It aims to identify and describe a series of circular processes and causal links that can be implemented based on deep study in SSA and ICAq. Circular processes to treat by-products in ICAq include components like composting, vermicomposting, aerobic and anaerobic digestion, silage, and insect production. These processes can produce ICAq inputs such as seedling substrates, plant fertilizers, bioenergy, or feed ingredients. In addition, the plant component can supply therapeutic compounds. Further research on characterization of aquaponic components outputs and its quantifications, the impact of using circular inputs generated within the ICAq, and the technical feasibility and economic viability of circular processes in the context of SSA is needed. Full article

The sustainable utilization of forest biomass for bioenergy production is increasingly challenged by the variability and unpredictability of raw material availability. These challenges are particularly critical in regions like Central Portugal, where seasonality, dispersed resources, and wildfire prevention policies disrupt procurement planning. This study investigates two flexibility strategies—dynamic network reconfiguration and operations postponement—as policy relevant tools to enhance resilience in forest-to-bioenergy supply chains. A novel mathematical model, the mobile Facility Location Problem with dynamic Operations Assignment (mFLP-dOA), is proposed and solved using a scalable matheuristic approach. Applying the model to a real case study, we demonstrate that incorporating temporary intermediate nodes and adaptable processing schedules can reduce costs by up to 17% while improving operational responsiveness and reducing non-productive machine time. The findings offer strategic insights for policymakers, biomass operators, and regional planners aiming to design more adaptive and cost-effective biomass supply systems, particularly under environmental risk scenarios such as summer operation bans. This work supports evidence-based planning and investment in flexible logistics infrastructure for cleaner and more resilient bioenergy supply chains. Full article

As global energy demand continues to rise, microalgae have gained attention as a promising feedstock for biofuel production due to their environmental adaptability and renewable nature. This study investigated the growth performance and stress tolerance of Desmodesmus sp. KNUA231 under varying pH and salinity conditions to evaluate its potential as a biofuel candidate. The strain was cultivated under controlled laboratory conditions and exhibited stable growth across a broad pH range (4–10) and moderate salinity levels (up to 5 g L⁻¹ NaCl), indicating its resilience to diverse environmental conditions. Fatty acid methyl ester (FAME) analysis revealed that the biodiesel properties of Desmodesmus sp. KNUA231 comply with ASTM and EN standards in specific parameters, reinforcing its feasibility as a renewable biofuel feedstock. Additionally, its high calorific value (CV) suggests its potential as an energy-dense biomass source. The results of inductively coupled plasma mass spectrometry (ICP) analysis show that the soil is supplied with essential nutrients while minimizing heavy metal contamination, suggesting the possibility of biofertilizers. Although Desmodesmus sp. KNUA231 demonstrated promising characteristics for biofuel applications, further research is required to optimize large-scale cultivation and improve productivity for industrial applications. These findings highlight the potential of Desmodesmus sp. KNUA231 as a biofuel resource, particularly in non-optimal environmental conditions where pH and salinity fluctuations are common, contributing to the ongoing search for sustainable bioenergy solutions. Full article