Search Results (49)

Gasification of municipal solid waste and other biogenic residues (e.g., biomass and biowaste) is increasingly recognized as a promising thermochemical pathway for converting non-recyclable fractions into valuable energy carriers, with applications in electricity generation, district heating, hydrogen production, and synthetic fuels. This paper provides a comprehensive analysis of major gasification technologies, including fixed bed, fluidized bed, entrained flow, plasma, supercritical water, microwave-assisted, high-temperature steam, and rotary kiln systems. Key aspects such as feedstock compatibility, operating parameters, technology readiness level, and integration within circular economy frameworks are critically evaluated. A comparative assessment of incineration and pyrolysis highlights the environmental and energetic advantages of gasification. The valorization pathways for main product (syngas) and by-products (syngas, ash, tar, and biochar) are also explored, emphasizing their reuse in environmental, agricultural, and industrial applications. Despite progress, large-scale adoption in Europe is constrained by economic, legislative, and technical barriers. Future research should prioritize scaling emerging systems, optimizing by-product recovery, and improving integration with carbon capture and circular energy infrastructures. Supported by recent European policy frameworks, gasification is positioned to play a key role in sustainable waste-to-energy strategies, biomass valorization, and the transition to a low-emission economy. Full article

Background: Sustainability is a critical concern in transportation, notably in light of governmental initiatives such as cap-and-trade systems and eco-label regulations aimed at reducing emissions. In this context, collaborative approaches among carriers, which involve the exchange of shipment requests, are increasingly recognized as effective strategies to enhance efficiency and reduce environmental impact. Methods: This research proposes a novel collaborative planning model for multimodal transport designed to minimize the total costs associated with freight movements, including both transportation and $C{O}_2$ emissions costs. Transshipments of freight between vehicles are modeled in the proposed formulation, promoting carrier coalitions. This study incorporated eco-labels, representing different emission ranges, to capture shipper sustainability preferences and integrated authority-imposed low-emission zones as constraints. A bi-objective approach was adopted, combining transportation and emission costs through a weighted sum method. Results: A case study on the Naples Bypass network (Italy) is presented, highlighting the model’s applicability in a real-world setting and demonstrating the effectiveness of collaborative transport planning. In addition, the model quantified the benefits of collaboration under low-emission zone (LEZ) constraints, showing notable reductions in both total costs and emissions. Conclusions: Overall, the proposed approach offers a valuable decision support tool for both carriers and policymakers, enabling sustainable freight transportation planning. Full article

Achieving global net-zero emissions by 2050 demands integrated and scalable strategies that unite decarbonization technologies across sectors. This review provides a forward-looking synthesis of carbon capture and storage and hydrogen systems, emphasizing their integration through artificial intelligence to enhance operational efficiency, reduce system costs, and accelerate large-scale deployment. While CCS can mitigate up to 95% of industrial CO₂ emissions, and hydrogen, particularly blue hydrogen, offers a versatile low-carbon energy carrier, their co-deployment unlocks synergies in infrastructure, storage, and operational management. Artificial intelligence plays a transformative role in this integration, enabling predictive modeling, anomaly detection, and intelligent control across capture, transport, and storage networks. Drawing on global case studies (e.g., Petra Nova, Northern Lights, Fukushima FH2R, and H21 North of England) and emerging policy frameworks, this study identifies key benefits, technical and regulatory challenges, and innovation trends. A novel contribution of this review lies in its AI-focused roadmap for integrating CCS and hydrogen systems, supported by a detailed analysis of implementation barriers and policy-enabling strategies. By reimagining energy systems through digital optimization and infrastructure synergy, this review outlines a resilient blueprint for the transition to a sustainable, low-carbon future. Full article

The enduring problem of CO₂ emissions and their consequent influence on the earth’s atmosphere has captured the attention of researchers. Photocatalytic CO₂ reduction holds great significance; however, it is constrained by the effect of carrier recombination. Simultaneously, the structural modification of heterojunction catalysts has emerged as a promising approach to boost the photocatalytic performance. Herein, Zn₂GeO₄@CeO₂ core@shell nanorods were prepared by a simple self-assembly method for photocatalytic CO₂ reduction. The thickness of the CeO₂ shell can be regulated rapidly and conveniently. The photocatalytic results indicate that the structure regulation could affect the photocatalytic performance by controlling the amount of active sites and the shielding effect. X-ray photoelectron spectroscopy (XPS) and Mott–Schottky analyses reveal that Zn₂GeO₄ and CeO₂ formed Type-I heterojunctions, which prolonged the lifetime of the photogenerated carriers. The CO₂ adsorption and activation capacities of CeO₂ also exert a beneficial influence on the progress of CO₂ photoreduction, thus enabling efficient photocatalytic CO₂ reduction. Moreover, the in situ FT-IR spectra show that Zn₂GeO₄@CeO₂ suppresses the formation of byproduct intermediates and shows higher CO selectivity. The best sample of Zn₂GeO₄@0.07CeO₂ can exhibit a CO yield of as high as 1190.9 μmol g⁻¹ h⁻¹. Full article

Green ammonia, as a zero-carbon energy carrier, has emerged as a core process for achieving energy transition and chemical industry decarbonization through renewable energy-powered electrolytic hydrogen production integrated with low-carbon Haber–Bosch ammonia synthesis. However, the strong coupling among multiple units in green ammonia production systems, combined with operational data characteristics of nonlinearity, uncertainty, noise interference, and multi-timescale dynamics, creates significant challenges in accurately predicting ammonia yields and key process indicators, ultimately hindering online process parameter optimization and restricting improvements in production efficiency with effective carbon emission control. To address this, this study proposes a dual-layer attention LSTM model. The architecture constructs two sequential attention mechanisms: the first layer being an input attention mechanism for screening critical process indicators, followed by the second layer as a temporal attention mechanism that dynamically captures time-varying feature weights, enabling the adaptive analysis of sub-window contribution discrepancies to output variables across multiple time steps. Furthermore, the model is implemented and validated on a simulation platform of a renewable energy-coupled green ammonia demonstration project, with comparative analyses conducted against conventional LSTM and other baseline models. Experimental results demonstrate that the proposed model effectively adapts to complex scenarios in green ammonia production, including fluctuating renewable energy inputs and time-varying reaction conditions, providing reliable support for yield prediction and energy efficiency optimization. The developed methodology not only provides a novel approach for intelligent modeling of green ammonia production systems but also establishes a technical foundation for digital twin-based real-time control and dynamic scheduling research. Full article

The increase in CO₂ emissions has been identified as a core driving factor in the intensification of the greenhouse effect. In order to achieve the dual-carbon vision, research on CO₂ capture and its catalytic conversion is receiving growing attention. Due to the high chemical stability of CO₂ itself, traditional separation technologies find it difficult to capture it onto catalysts. Currently, using hydrocarbons as carriers for catalytic reactions is the most common and efficient method. In recent years, metal-organic frameworks (MOFs) have shown their irreplaceable importance in CO₂ capture and catalytic conversion due to their unique adjustable and controllable pore structures and multiple active sites. This study integrates various classification criteria of MOFs, proposes a cooperative mechanism between metal doping and functional groups, and also reveals the CO₂ capture and catalytic conversion processes. In addition, we have conducted an in-depth discussion on the future development of continuous-flow microreactor technology and provided performance and property relationship diagrams for multiple MOF series, offering valuable reference material for future research in related fields. Full article

Berthing operation heterogeneity across ship types causes significant uncertainty in assessing port congestion and carbon emissions over comparable timeframes. This study quantifies in-port emission dynamics for four cargo ship types (container, liquid bulk, dry bulk, and general cargo) using an operational phase-specific emission accounting model. We propose a hybrid deep learning model that integrates Two-Dimensional Convolutional Neural Networks (2DCNN) with Squeeze-and-Excitation Attention Mechanisms (SEAM) and Bidirectional Long Short-Term Memory Networks (BiLSTM) layers, optimized via the Triangulation Topology Aggregation Optimizer (TTAO) for hyperparameter tuning. Empirical analysis at Ningbo Zhoushan Port shows that liquid bulk carriers emit 23–41% more than other ship types due to extended auxiliary engine/boiler use during cargo handling. The 2DCNN-SEAM model significantly improves BiLSTM prediction accuracy—reducing Mean Absolute Percentage Error (MAPE) by 18.7% and increasing the R² value to 0.94—by effectively capturing spatiotemporal congestion features. Results confirm that operational congestion is a critical emission multiplier, especially for ships requiring prolonged auxiliary system use during berthing. These insights inform targeted decarbonization strategies for port authorities, prioritizing operational efficiency and energy transition for high-emission ship categories. Full article

Hydrogen energy is essential in the transition to sustainable transportation planning, providing a clean and efficient alternative to traditional fossil fuels. As a versatile energy carrier, hydrogen facilitates the decarbonization of diverse transportation modes, including passenger vehicles, heavy-duty trucks, trains, and maritime vessels. To justify and clarify the role of hydrogen energy in sustainable transportation planning, this study conducts a comprehensive techno-economic and environmental assessment of hydrogen production in the USA, Europe, and China. Utilizing the Shlaer–Mellor method for policy modeling, the analysis highlights regional differences and offers actionable insights to inform strategic decisions and policy frameworks for advancing hydrogen adoption. Hydrogen production potential was assessed from solar and biomass resources, with results showing that solar-based hydrogen production is significantly more efficient, producing 704 tons/yr/km², compared to 5.7 tons/yr/km² from biomass. A Monte Carlo simulation was conducted to project emissions and market share for hydrogen and gasoline vehicles from 2024 to 2050. The results indicate that hydrogen vehicles could achieve near-zero emissions and capture approximately 30% of the market by 2050, while gasoline vehicles will decline to a 60% market share with higher emissions. Furthermore, hydrogen production using solar energy in the USA yields a per capita output of 330,513 kg/yr, compared to 6079 kg/yr from biomass. The study concludes that hydrogen, particularly from renewable sources, holds significant potential for reducing greenhouse gas emissions, with policy frameworks in the USA, Europe, and China focused on addressing energy dependence, air pollution, and technological development in the transportation sector. Full article

Hybrid electric propulsion architectures offer a promising solution for reducing fuel consumption and emissions in aviation. However, the introduction of dual-energy carriers adds complexity to preliminary aircraft design, particularly in terms of power distribution, failure analysis, and compliance with operational regulations. Key challenges include defining failure cases, which requires refining conventional constraint analysis for hybrid electric aircraft and integrating failure scenarios into mission analysis to meet certification specifications and regulatory requirements. This study presents a unified methodology that combines an analytical constraint analysis with a higher-fidelity numerical design loop implemented in the SUAVE framework to address these challenges. Key innovations include the introduction of new parameters—such as the supplied shaft power ratio—and the ability to assess failure scenarios through the definition of the critical loss of thrust, thereby extending the analysis beyond conventional one-engine-inoperative cases. The methodology also integrates an energy management strategy that dynamically allocates power between the primary and secondary energy carriers, thereby capturing the interaction between energy (mission analysis) and power (constraint analysis) requirements. The results from both the constraint and mission analyses, including en-route alternate aerodrome scenarios, demonstrate that employing batteries as the secondary energy carrier can reduce the oversizing of primary power sources. However, their effective utilization is highly sensitive and may necessitate adjustments in energy sizing. These findings underscore the importance of incorporating dual-energy carrier considerations early in the design process and highlight the impact of critical loss of thrust conditions on hybrid electric aircraft configurations, ultimately benefiting researchers and engineers. Full article

Membrane technology has been widely used in industrial CO₂ capturing, gas purification and gas separation, arousing attention due to its advantages of high efficiency, energy saving and environmental protection. In the context of reducing global carbon emissions and combating climate change, it is particularly important to capture and separate greenhouse gasses such as CO₂. Zr-MOF can be used as a multi-dimensional modification on the polymer membrane to prepare self-assembled MOF-based mixed matrix membranes (MMMs), aiming at the problem of weak adhesion or bonding force between the separation layer and the porous carrier. When defective UiO-66 is applied to PVDF membrane as a functional layer, the CO₂ separation performance of the PVDF membrane is significantly improved. TUT-UiO-3-TTN@PVDF has a CO₂ permeation flux of 14,294 GPU and a selectivity of 27 for CO₂/N₂ and 18 for CO₂/CH₄, respectively. The CO₂ permeability and selectivity of the membrane exhibited change after 40 h of continuous operation, significantly improving the gas separation performance and showing exceptional stability for large-scale applications. Full article

Chemical looping combustion (CLC) emerges as a cost-effective CO₂ capture technology, demonstrating high competitiveness for both industrial and energy applications. This study explores the synthesis of a Cu-based, praseodymium (Pr)-modified gamma-alumina-supported (20CuPA) oxygen carrier (OC) through the wet impregnation method and investigates its performance in CLC. The characteristics of the synthesized OC were investigated using field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, temperature-programmed reduction analysis, and X-ray diffraction analysis. The CLC of methane gas was performed in a thermogravimetric analyzer (TA-Q50). The oxygen transport capacity (OTC) of the 20CuPA-based OC was investigated for 10 redox cycles. The impact of temperature and time as process variables in determining the OTC of OCs was studied. The TGA results indicated that the most important factor influencing the optimization of the OTC of OCs was time. In comparison to time, temperature had less of an impact on the OTC of 20CuPA-OC. The maximum OTC of 20CuPA-OC, which was 0.0546 mg of O₂/mg of OC, was reached using optimized process variables, including a temperature of 800 °C and a time of 3 min. Full article

The growing emphasis on renewable energy highlights hydrogen’s potential as a clean energy carrier. However, traditional hydrogen production methods contribute significantly to carbon emissions. This review examines the integration of carbon capture and storage (CCS) technologies with hydrogen production processes, focusing on their ability to mitigate carbon emissions. It evaluates various hydrogen production techniques, including steam methane reforming, electrolysis, and biomass gasification, and discusses how CCS can enhance environmental sustainability. Key challenges, such as economic, technical, and regulatory obstacles, are analyzed. Case studies and future trends offer insights into the feasibility of CCS–hydrogen integration, providing pathways for reducing greenhouse gases and facilitating a clean energy transition. Full article

E-fuels represent a crucial technology for transitioning to fossil-free energy systems, driven by the need to eliminate dependence on fossil fuels, which are major environmental pollutants. This study investigates the production of carbon-neutral synthetic fuels, focusing on e-hydrogen (e-H₂) generated from water electrolysis using renewable electricity and carbon dioxide (CO₂) captured from industrial sites or the air (CCUS, DAC). E-H₂ can be converted into various e-fuels (e-methane, e-methanol, e-DME/OME, e-diesel/kerosene/gasoline) or combined with nitrogen to produce e-ammonia. These e-fuels serve as efficient energy carriers that can be stored, transported, and utilized across different energy sectors, including transportation and industry. The first objective is to establish a clear framework encompassing the required feedstocks and production technologies, such as water electrolysis, carbon capture, and nitrogen production techniques, followed by an analysis of e-fuel synthesis technologies. The second objective is to evaluate these technologies’ technological maturity and sustainability, comparing energy conversion efficiency and greenhouse gas emissions with their electric counterparts. The sustainability of e-fuels hinges on using renewable electricity. Challenges and future prospects of an energy system based on e-fuels are discussed, aiming to inform the debate on e-fuels’ role in reducing fossil fuel dependency. Full article

We study recombination processes in nitride LEDs emitting from 270 to 540 nm with EQE ranging from 4% to 70%. We found a significant correlation between the LEDs’ electro-optical properties and the degree of nanomaterial disorder (DND) in quantum wells (QWs) and heterointerfaces. DND depends on the nanoarrangement of domain structure, random alloy fluctuations, and the presence of local regions with disrupted alloy stoichiometry. The decrease in EQE values is attributed to increased DND and excited defect (ED) concentrations, which can exceed those of Shockley–Read–Hall defects. We identify two mechanisms of interaction between EDs and charge carriers that lead to a narrowing or broadening of electroluminescence spectra and increase or decrease EQE, respectively. Both mechanisms involve multiphonon carrier capture and ionization, impacting EQE reduction and efficiency droop. The losses caused by these mechanisms directly affect EQE dependencies on current density and the maximum EQE values for LEDs, regardless of the emission wavelength. Another manifestation of these mechanisms is the reversibility of LED degradation. Recombination processes vary depending on whether QWs are within or outside the space charge region of the p-n junction. Full article

Hydrogen is an industrial raw material both for the production of chemicals and for oil refining with hydrotreating. It is the subject of increasing attention for its possible use as an energy carrier and as a flexible energy storage medium. Its production is generally accomplished in Steam Methane Reforming (SMR) plants, where a gaseous mixture of CO and H₂, with a limited number of other species, is obtained. The process of production and purification generates relevant amounts of carbon dioxide, which needs to be removed due to downstream process requirements or to limit its emissions to the atmosphere. A work by IEAGHG focused on the study of a state-of-the-art Steam Methane Reforming plant producing 100 kNm³/h of H₂ and considered chemical absorption with MethylDiEthanolAmine (MDEA) solvent for removing carbon dioxide from the PSA tail gas in a baseline scheme composed of the absorber, one flash vessel and the regeneration column. This type of process is characterized by high energy consumption, in particular at the reboiler of the regeneration column, usually operated by employing steam, and modifications to the baseline scheme can allow for a reduction of the operating costs, though with an increase in the complexity of the plant. This work analyses three configurations of the treatment section of the off gas obtained after the purification of the hydrogen stream in the Pressure Swing Adsorption unit with the aim of selecting the one which minimizes the overall costs so as to further enhance Carbon Capture and Storage in non-power industries as well. Full article