Search Results (591)

This paper introduces a mathematical model to assess the polluting impact of the decarbonization options for medium-sized High-Speed Crafts in the EU, and their consequences in terms of Market-Based Measure costs and Goal-Based Measure compliance under expected regulatory scenarios. This model is applied to a particular European High-Speed Craft operating in the Canary Islands. Considering slow steaming along with High Speed Craft’s retrofitting with alternative technologies for its electricity supply, we conclude that green H₂ fuel Cells provide the greatest environmental advantage by comparison with slow steaming alone, achieving a 6.96% improvement in emissions and savings under European Market-Based Measures of 39.76% by 2033. The expected regulative progression involves a 5.90% improvement in the Market-Based Measure costs’ convergence with the actual pollution impact of High-Speed Crafts. The findings warn about the pressing need to review the implementation of On-Shore Power Supply emissions into the Fuel EU fines, and about a concerning pull effect for the most polluting European High-Speed Crafts are moved towards the outermost regions of the EU due to their permanent exceptions from the application of the European Market-Based Measures. Full article

Biofuels have emerged as a promising alternative to conventional fuels, offering improved environmental sustainability. Nevertheless, inadequate control of their physicochemical properties can lead to increased emissions and potential engine damage. Existing methods for regulating these properties depend on costly and sophisticated laboratory equipment, which poses significant challenges for integration into industrial production processes. Three-dimensional printing technology provides a cost-effective alternative to traditional fabrication methods, offering particular benefits for the development of low-cost designs for detecting liquid properties. In this work, we present a sensor system for assessing biofuel solutions. The presented device employs piezoelectric sensors integrated with 3D-printed, liquid-filled cells whose structural design is refined through experimental validation and novel optimization strategies that account for sensitivity, recovery and resolution. This system incorporates discrete electronic circuits and a microcontroller, within which artificial intelligence algorithms are implemented to correlate sensor responses with fluid viscosity and density. The proposed approach achieves calibration and resolution errors as low as 0.99% and $1.48\times {10}^{-2}$ mPa·s for viscosity, and 0.0485% and $1.9\times {10}^{-4}$ g/mL for density, enabling detection of small compositional variations in biofuels. Additionally, algorithmic methodologies for dimensionality reduction and data treatment are introduced to address temporal drift, enhance sensor lifespan and accelerate data acquisition. The resulting system is compact, precise and applicable to diverse industrial liquids. Full article

Microbial fuel cells (MFCs) are a promising technology for simultaneously treating wastewater and recovering energy, yet scaling them from lab prototypes to practical systems poses persistent challenges. This review addresses the scale-up gap by systematically examining recent pilot-scale MFC studies from multiple perspectives, including reactor design configurations, materials innovations, treatment performance, energy recovery, and environmental impact. The findings show that pilot MFCs reliably achieve significant chemical oxygen demand (COD) removal (often 50–90%), but power densities remain modest (typically 0.1–10 W m⁻³)—far below levels needed for major energy generation. Key engineering advances have improved performance; modular stacking maintains higher power output, low-cost electrodes and membranes reduce costs (with some efficiency trade-offs), and power-management strategies mitigate issues like cell reversal. Life cycle assessments indicate that while MFC systems can outperform conventional treatment in specific scenarios, overall sustainability gains depend on boosting energy yields and optimizing materials. The findings highlight common trade-offs and emerging strategies. By consolidating recent insights, a roadmap of design principles and research directions to advance MFC technology toward sustainable, energy-positive wastewater treatment was outlined. Full article

Decarbonizing industry, improving urban sustainability, and expanding clean energy use are key global priorities. This study presents a techno-economic analysis (TEA) and life-cycle assessment (LCA) of green hydrogen (GH₂) production via water electrolysis for low-carbon applications in the Central Asian region, with Uzbekistan considered as a representative case study. Solar PV and wind power are used as renewable electricity sources for a 44 MW electrolyzer. The assessment also incorporates recent advances in alkaline water electrolyzers (AWE) enhanced with metal–organic framework (MOF) materials, reflecting improvements in efficiency and hydrogen output. The LCA, performed using SimaPro, evaluates the global warming potential (GWP) across the full hydrogen production chain. Results show that the MOF-enhanced AWE system achieves a lower levelized cost of hydrogen (LCOH) at 5.18 $/kg H₂, compared with 5.90 $/kg H₂ for conventional AWE, with electricity procurement remaining the dominant cost driver. Environmentally, green hydrogen pathways reduce GWP by 80–83% relative to steam methane reforming (SMR), with AWE–MOF delivering the lowest footprint at 1.97 kg CO₂/kg H₂. In transport applications, fuel cell vehicles powered by hydrogen derived from AWE–MOF emit 89% less CO₂ per 100 km than diesel vehicles and 83% less than using SMR-based hydrogen, demonstrating the substantial climate benefits of advanced electrolysis. Overall, the findings confirm that MOF-integrated AWE offers a strong balance of economic viability and environmental performance. The study highlights green hydrogen’s strategic role in the Central Asian region, represented by Uzbekistan’s energy transition, and provides evidence-based insights for guiding low-carbon hydrogen deployment. Full article

This study investigates whether Battery Electric Vehicles (BEVs) or Fuel Cell Electric Vehicles (FCEVs) represent the superior alternative to conventional vehicles for last-mile delivery, with a particular focus on large enterprises that prioritize both economic feasibility and environmental performance. Life Cycle Assessment and Life Cycle Cost methodologies are applied to evaluate both technologies across the full cradle-to-grave life cycle within a unified framework. The functional unit is defined as one kilometer traveled by a BEV or FCEV in last-mile transportation, and the system boundary includes vehicle manufacturing, operation, maintenance, and end-of-life treatment. The environmental impacts are assessed using the ReCiPe 2016 Midpoint (H) method implemented in OpenLCA 2.0.4, and normalization follows the standards provided by the official ReCiPe 2016 framework. The East China Power Grid serves as the baseline electricity mix for the operational stage. Regarding GHG emissions, FCEVs demonstrate a 12.36% reduction in carbon dioxide (CO₂) emissions compared to BEVs. This reduction is particularly significant during the operational phase, where FCEVs can lower CO₂ emissions by 53.51% per vehicle relative to BEVs, largely due to hydrogen energy’s higher efficiency and durability. In terms of economic costs, BEVs hold a slight advantage over FCEVs, costing approximately 0.8 RMB/km/car less. However, during the manufacturing phase, FCEVs present greater environmental challenges. It is recommended that companies fully consider which environmental issues they wish to make a greater contribution to when selecting vehicle types. This study provides insight and implications for large companies with financial viability concerns about environmental impact regarding selecting the two types of vehicles for last-mile transportation. The conclusions offer guidance for companies assessing which vehicle technology better aligns with their long-term operational and sustainability priorities. It can also help relevant practitioners and researchers to develop solutions to last-mile transportation from the perspective of different enterprise sizes. Full article

Fuel cells offer a promising route to eliminating in-flight emissions from regional aviation, but certification requires proof that stacks can withstand the vibration and shock environment of turboprop aircraft. As part of the EU-funded NEWBORN project, we combined detailed finite element modeling with shaker tests to evaluate the vibration immunity of PowerCell Group’s prototype stack. The numerical model combined an orthotropic, two-zone 3D mesh of the cell package with reduced-order representations of plates, compression bands, disc springs and the mounting cage. The assembled stack was excited between 10 and 300 Hz using pseudo-random and sine-sweep inputs up to 2.0 g, from which 54 frequency response functions were obtained. The tuned model accurately reproduced the first global modes and captured the overall dynamic behavior with good, though not perfect, agreement. The combined numerical–experimental methodology therefore offers a framework for refining test campaigns and delivering early, qualitative evidence of vibration immunity in fuel cell stacks destined for flight. Full article

Maritime transport accounts for approximately 80–90% of global trade and nearly 3% of global greenhouse gas (GHG) emissions. In response, the International Maritime Organization (IMO) adopted an ambitious strategy for net-zero emissions by 2050, critically mandating a Well-to-Wake (WtW) life-cycle assessment for fuels. This framework invalidates fuels produced with high carbon intensity, regardless of their emissions at the point of use, thereby compelling the industry to focus on truly clean and sustainable alternatives. This push positions green hydrogen and ammonia as leading solutions, though they present a distinct trade-off. Hydrogen is an ideal fuel with zero-carbon emission in fuel cells but faces significant storage challenges due to its extremely low volumetric energy density and cryogenic requirements. In contrast, ammonia offers superior energy density and easier handling but contends with issues of toxicity and potentially harmful emissions like nitrous oxide. This paper provides a comprehensive review of this complex landscape, analyzing the production, utilization, and associated techno-economic and geopolitical challenges of using hydrogen and ammonia as future marine fuels, with environmental aspects briefly considered. Full article

Accurate modeling of proton exchange membrane fuel cells (PEMFCs) is essential for predicting system performance under diverse operating conditions. This study introduces a refined semi-empirical modeling that combines experimental validation with an enhanced parameter estimation method based on the Cloud Drift Optimization (CDO) algorithm. The approach focuses on identifying seven key parameters of the nonlinear PEMFC model by minimizing the difference between experimentally measured and simulated cell voltages. To assess its effectiveness, the proposed CDO-based estimator was compared with several established metaheuristic algorithms, including the particle swarm optimizer and the tetragonula carbonaria optimization algorithm. The evaluation was performed using three commercial PEMFC stacks rated at 250 W, 500 W, and the NedStack PS6, as well as experimental data obtained from the Renewable Energy Laboratory at A’Sharqiyah University. Results demonstrate that the CDO algorithm consistently produced the lowest sum of squared errors (SSE) of 1.0337 and exhibited stable convergence across multiple independent runs with a standard deviation of 1.2114 × 10⁻⁷. Its reliable performance under both normal and degraded conditions confirms the algorithm’s robustness and adaptability, establishing CDO as an efficient and dependable technique for PEMFC modeling and parameter identification. Full article

This study addresses the critical issue of fossil fuel dependence and its environmental impacts by examining bioelectrochemical systems (BES) for converting CO₂ into sustainable biofuels. A bibliometric analysis was conducted on 87 Scopus documents (2010–2025) using RStudio (Bibliometrix) and VOSviewer to map co-authorship, co-citation, and keyword networks. Results show exponential growth since 2017, dominated by Environmental Science, Chemical Engineering, and Energy. China leads in publication volume, while Belgium excels in international collaboration and impact per article. Research networks are concentrated in Europe and Asia, with significant underrepresentation of Latin America and Africa. Thematic clusters center on CO₂, microbial fuel cells, and bioenergy, indicating a shift toward material and process optimization. Influential authors such as Bajracharya S. focus on microbial electrosynthesis. However, key research gaps persist: limited integration of direct carbon capture technologies, inadequate biofilm characterization, and a scarcity of industrial-scale studies. Moreover, fewer than 10% of studies include comprehensive life cycle assessments (LCA) to evaluate the environmental footprint of BES. We propose a standardized LCA framework integrating techno-economic and circular economy metrics to advance BES from lab-scale proofs-of-concept to industrially viable, net-negative carbon technologies. The analysis also underscores a critical gap in policy and regulatory research, which is essential to create enabling conditions for the demonstration and scaling of BES technologies. Full article

The study examines the influence of diverse flue gas compositions on the operational parameters and efficiency of MCFCs (molten carbonate fuel cells) as CO₂ separation devices to provide foundational knowledge on MCFC operation under various industrial conditions. MCFCs inherently rely on the presence of CO₂ at the cathode, where it combines with oxygen to form carbonate ions that migrate through the electrolyte; thus, CO₂ acts as a carrier species rather than a fuel, enabling simultaneous electricity generation and CO₂ separation. The findings indicate that MCFCs are most effective when operated with CO₂-rich flue gases, such as those from coal and lignite-fired power plants with CO₂ contents of roughly 12–15 vol.% and O₂ contents of 2–6 vol.%. In these cases, CO₂ reduction rates of up to 80% can be achieved while maintaining favorable cell voltages. Under such conditions, relevant also for the cement industry (CO₂ between 15 and 35 vol.%), the Nernst voltage can reach about 1.18 V. In contrast, flue gases from gas turbines, which typically contain only 4–6 vol.% CO₂ and 11–13 vol.% O₂, result in lower Nernst voltages (0.6–0.7 V) and a decrease in efficiency. To address this issue, potential modifications to the MCFC electrolyte are suggested to enhance oxygen-ion conductivity and improve performance. By quantifying the operational window and CO₂-reduction potential for different sectors at 650 °C and 1 atm using a reduced-order model, the paper provides a technology assessment that supports sustainable industrial operation and the design of CCS (carbon capture and sequestration) strategies in line with climate goals. Full article

This study investigates the potential of proton exchange membrane fuel cells (PEMFCs) for application in the transport sector through a numerical modelling approach, evaluating their performance and alignment with the European Union’s climate objectives. The model’s performance was assessed by calculating the percentage error across the operating range, that were found to range from a minimum of 0.045% to a maximum of 2.913% across current densities up to 0.80 A/cm². The objective is to assess the viability of PEMFCs as a clean alternative to internal combustion engines and to identify the key technical and policy challenges hindering their wider adoption. Full article

Organic photovoltaics (OPVs) based on non-fullerene acceptors (NFAs) are rapidly advancing as lightweight, flexible, and low-cost solar technologies, with power conversion efficiencies approaching 20%. To ensure that environmental sustainability progresses symmetrically alongside performance improvements, it is essential to quantify the environmental footprint of these emerging technologies, particularly during early development stages when material and process choices remain adaptable. This study presents a cradle-to-gate life cycle assessment (LCA) of PTB7-Th:ZY-4Cl solar cells, aiming to identify asymmetries in environmental impact distribution and guide eco-efficient optimization strategies. Using laboratory-scale fabrication data, global warming potential (GWP), cumulative energy demand (CED), acidification (AP), eutrophication (EP), and fossil fuel depletion (FFD) were evaluated via the TRACI methodology. Results reveal that electricity consumption in thermomechanical operations (ultrasonic cleaning, spin coating, annealing, and stirring) disproportionately dominates most impact categories, while chemical inputs such as PEDOT:PSS, PTB7-Th:ZY-4Cl precursors, and solvents contribute significantly to fossil fuel depletion. Substituting grid electricity with renewable sources (hydro, wind, PV) markedly reduces GWP, and solvent recovery or replacement with greener alternatives offers further gains. Although extrapolation to a 1 m² pilot-scale module reveals impacts higher than established PV technologies, prospective scenarios with realistic efficiencies (10%) and lifetimes (10–20 years) suggest values of ~150–500 g CO₂-eq/kWh—comparable to fullerene OPVs and approaching perovskite and thin-film benchmarks. These findings underscore the value of early-stage LCA in identifying asymmetrical hotspots, informing material and process optimization, and supporting the sustainable scale-up of next-generation OPVs. Full article

Nonrenewable energy sources dominate global energy production, but their depletion and environmental impact pose serious challenges. The need for alternative and eco-friendly energy sources is increasingly evident. In this regard, utilizing knowledge gained from natural microorganisms to generate bioelectricity is a promising solution via microbial fuel cells (MFCs). Microbial fuel cells are an environmentally friendly technology that generates power from diverse organic substrates through the ‘catalytic’ activity of microorganisms. Although, MFCs still generate relatively low power, various scale-up studies have shown noticeable improvements in power output. Among the available strategies, mixed-culture systems are the simplest, sustainable, and direct way to improve bioelectricity production. However, the mixed culture microbial synergistic interactions and competition that drive power generation remain poorly understood. To address this, the objective of this review is to assess how synergistic interactions and metabolic networks within mixed microbial cultures enhance bioelectricity generation in microbial fuel cells. This review also explores the mixed-culture microbial fuel cell system as a promising renewable technology with potential applications in sustainable energy production. Full article

It is well established that solar cells convert solar energy into electrical energy, thereby contributing to environmental sustainability by reducing dependence on fossil fuels. In the present study, thin films composed of different materials were employed with the aim of mitigating efficiency losses in polycrystalline solar cells, which operate at a specific output voltage of 0.5 V. To evaluate the performance of these films, solar irradiation tests were conducted in Ciudad Obregón, Sonora, Mexico, during periods that accounted for both seasonal and diurnal variations in solar irradiance. The experiments were carried out during peak solar hours, a time frame that represents the conditions of highest thermal stress and irradiance intensity and is therefore relevant for analyzing heat-related efficiency losses. The thin films investigated included silver nanoparticles, copper sulfide, potassium permanganate, zinc sulfide, and lead sulfide. An improvement of 0.5% in open circuit voltage gain was achieved, corresponding to a temperature difference of 13.5 °C between the hottest and coolest cells. Notably, the cells that exhibited efficiency enhancement were those incorporating silver nanoparticles and potassium permanganate, with varying deposition times in the chemical bath. Among these, the latter demonstrated superior performance (KMnO₄ performed best). So, the objective of this experimental work was to assess the effect of various thin film coatings on the performance of polycrystalline silicon solar cells under natural sunlight. Full article

Rising energy demand, fossil fuel depletion, and global warming are accelerating research into sustainable energy solutions, with growing interest in hydrogen as a promising alternative. This research presents a detailed experimental investigation and novel digital twin (DT) models for an integrated hydrogen-based energy system consisting of an Anion Exchange Membrane Electrolyzer (AEMEL), Proton Exchange Membrane Fuel Cell (PEMFC), hydrogen storage, and Battery Energy Storage System (BESS). Conducted at a real-world facility in Risavika, Norway, the study employed commercial units: the Enapter EL 4.1 AEM electrolyzer and Intelligent Energy IE-Lift 1T/1U PEMFC. Experimental tests under dynamic load conditions demonstrated stable operation, achieving hydrogen production rates of up to 512 NL/h and a specific power consumption of 4.2 kWh/Nm³, surpassing the manufacturer’s specifications. The PEMFC exhibited a unique cyclic operational mechanism addressing cathode water flooding, a critical issue in fuel cell systems, achieving steady-state efficiencies around 43.6% under prolonged (190 min) rated-power operation. Subsequently, advanced DT models were developed for both devices: a physics-informed interpolation model for the AEMEL, selected due to its linear and steady operational behavior, and an ANN-based model for the PEMFC to capture its inherently nonlinear, dynamically fluctuating characteristics. Both models were validated, showing excellent predictive accuracy (<3.8% deviation). The DTs integrated manufacturer constraints, accurately modeling transient behaviors, safety logic, and operational efficiency. The round-trip efficiency of the integrated system was calculated (~27%), highlighting the inherent efficiency trade-offs for autonomous hydrogen-based energy storage. This research significantly advances our understanding of integrated H₂ systems, providing robust DT frameworks for predictive diagnostics, operational optimization, and performance analysis, supporting the broader deployment and management of hydrogen technologies. Full article