Search Results (84)

As the energy and power sector transitions toward clean and low-carbon development, the installed capacity of renewable energy sources such as wind and photovoltaic power has been rapidly increasing. Wind–solar hydrogen production via water electrolysis can enhance renewable energy utilization and enable the supply of green hydrogen. Meanwhile, the $H_2/C{O}_2$ molar ratio in the syngas produced by conventional biomass gasification generally cannot directly meet the 2:1 stoichiometric requirement for methanol synthesis. To address this issue, this paper proposes an off-grid coordinated system integrating wind–solar hydrogen production and biomass gasification for methanol synthesis. The system incorporates multi-operating-condition constraints of electrolyzers, coordinated regulation between electrochemical energy storage and hydrogen storage, and coordinated matching between biomass gasification and the water–gas shift reaction. Based on the system energy and material balance, a mixed-integer linear programming (MILP) model is formulated with the objective of minimizing the annualized total cost and is solved using the Gurobi solver in the MATLAB environment. To highlight the roles of HES and the WGS reaction, four comparative scenarios are designed for validation. The results show that the system with an annual methanol production capacity of 100,000 tons achieves an annualized total cost of 318 million CNY, with a wind–solar utilization rate of 98.86%. The system is configured with 12 electrolyzers of 5 MW each. The biomass consumption per ton of methanol is 3.06, and the $C{O}_2$ emissions per ton of methanol are 2.37. Finally, a sensitivity analysis of the levelized methanol cost (LCOM) was conducted, providing guidance for cost reduction in green methanol production. Full article

The electrochemical behavior of metallic rhenium was investigated using voltammetry and ex situ X-ray photoelectron spectroscopy (XPS) in aqueous acidic methanol solutions. Capacitance–potential analysis revealed that the double-layer current is governed by an adsorption–desorption surface process involving oxygen and sulfate species, as confirmed by XPS. The hydrogen evolution reaction (HER) proceeds via a Volmer–Heyrovsky mechanism, with hydrogen adatoms, physisorbed oxygen, and chemisorbed sulfate molecules as key intermediates. Methanol does not inhibit hydrogen gas production, and oxygenated species actively participate in the HER pathway. Voltammetric measurements demonstrated that rhenium cathodes are highly efficient for methanol electrolysis in membraneless systems, suggesting their potential application in electrolysis processes involving unpurified wastewater. These findings highlight rhenium as a promising electrode material for use in sustainable energy conversion technologies. Full article

Far offshore wind resources are important for reaching the global renewable energy and decarbonization objectives, but great distances to shore and deep waters preclude underwater electricity lines or traditional turbine or platform foundations. At these distances, converting the produced electricity to hydrogen via electrolysis of purified seawater is attracting interest. This hydrogen can then be transferred with fewer losses via undersea pipelines or transported to shore via ships. The difficulties of storing and transporting hydrogen over large distances can also be remedied by converting it into easily transported “e-fuels”, such as methanol and ammonia. The paper summarizes the current literature in terms of technologies and strategies involved in these renewable fuel production processes and highlights power consumption, efficiency, and levelized cost figures. These renewable e-fuels promise an environmentally friendly method of tapping into vast overseas resources that can be utilized on shore or provided to sea vessels for refueling. However, electrolyzer, synthesis reactor, and deep-water foundation or floating platform costs need to be brought down significantly by research and development before they can become commercially feasible in the coming decades. Full article

Copper-based catalysts have emerged as promising materials for electrochemical carbon dioxide reduction reactions, owing to copper’s unique ability to facilitate multi-electron transfer processes and produce valuable products such as methanol and ethanol. In this study, novel trisferrocenyltrithiophosphite–copper(I) bromide composites with Cu-to-ligand molar ratios of 1:1 and 2:1 were synthesized and evaluated for their catalytic performance. The composites were characterized by a combination of techniques, including powder X-ray diffraction (PXRD), linear sweep voltammetry (LSV), potentiostatic testing, chromatographic analysis, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical measurements demonstrated significant current enhancements in the presence of CO₂, highlighting the composites’ catalytic activity. Potentiostatic tests revealed excellent stability, with only a 9% decline in current density over 5 h of electrolysis. Product analysis via gas chromatography indicated the formation of methanol for the 1:1 composite and ethanol for the 2:1 composite with Faradaic efficiencies of 5.79% and 9.26%, respectively. While absolute efficiencies remain modest due to competitive hydrogen evolution, these results demonstrate a tunable catalytic performance based on the Cu-to-ligand ratio. SEM and XPS studies further supported the formation of active catalytic centers and changes in the oxidation states of copper during CO₂ reduction. PXRD analysis confirmed the retention of structural integrity for both composites before and after catalytic testing. Full article

Legal requirements are increasingly promoting the thermal treatment of sewage sludge in Germany, and alternative disposal methods are being investigated. Oxyfuel combustion is one promising thermal process for treating sewage sludge. However, the flue gas produced during the combustion process contains high levels of CO₂, a greenhouse gas that poses environmental harm. To address this issue, this study analyzed oxyfuel combustion and various CO₂ capture methods, aiming to utilize CO₂ as a feedstock for methanol production. Energy and material balance simulations were carried out using Aspen Plus. Four distinct carbon capture methods: membrane carbon capture, cryogenic carbon capture, monoethanolamine carbon capture, and ionic liquid carbon capture were modeled. Three different oxygen configurations were tested: pure air, pure oxygen, and a 50/50 air–oxygen mixture. The oxygen separation systems, including air separation units and alkaline electrolyzers, were also studied and modeled. As a result, 14 different scenarios were created. The performances, energy efficiency, and economic results of each scenario were compared to one another and to existing literature, allowing for the identification of the most effective approaches. The oxyfuel combustion scenarios achieved the highest methanol output. MEA and ionic liquid capture combined with air combustion proved to be the most cost-effective options, while cryogenic capture incurred the highest costs due to its helium-based cooling requirements. Although ASU-based oxyfuel combustion achieved the lowest specific energy requirement for methanol production, electrolysis-integrated configurations remained economically disadvantageous, underscoring the critical influence of electricity prices on the overall feasibility of the system. Full article

The article describes oxygen gasification installation for waste biomass in waste-to-fuel technology, in which the final product is liquid methanol (the reference case). A comprehensive techno-economic model integrates oxygen-based gasification of wet sludge with three waste-heat recovery technologies—expander, Stirling engine, and organic Rankine cycle—and directs the recovered electrical power to a PEM electrolyzer for additional hydrogen production. The model captures full material flows, thermodynamic efficiencies, CO₂ balances, and an economic analysis over a 20-year horizon. A comparison of the use of an expander, Stirling engines, and ORC modules to power the electrolytic hydrogen generation installation was proposed. The produced hydrogen is an additional substrate for the methanol reactor, which will consequently increase the methanol yield from the entire installation and reduce the specific CO₂ emissions. Oxygen from the electrolysis process can be used in the gasifier, which will reduce the energy consumption of the Air Separation Unit, and thus increase the efficiency of the entire gasification system. In addition to the technical evaluation, an economic analysis was carried out to assess the profitability of the proposed concepts, showing that process integration can significantly improve both energy performance and economic feasibility of methanol production in waste-to-fuel systems. Results show that proposed modifications have the potential to increase overall efficiency from 75.498% (reference scenario) to even 82.545% (best scenario), while specific emissions of carbon dioxide drop from 1.746 kg CO₂/kg CH₃OH (reference scenario) to 1.468 kg CO₂/kg CH₃OH (best scenario), with an increase in methanol yield of about 9.4% (from 0.255 kg CH₃OH/kg Bio in reference scenario to 0.279 in best scenario). Full article

The growing demand for renewable energy positions biorefineries as key to enhancing biofuel competitiveness. This study proposes a novel MILP superstructure integrating resource seasonality, process selection, and heat integration to optimize biomethanol production in a sugarcane biorefinery. A multi-objective optimization balancing net present value (NPV) and avoided CO₂ emissions reveals that energy integration improves environmental performance with limited economic impact. The model estimates the production of up to 66.85 kg of biomethanol/ton sugarcane from bagasse gasification, 40.7 kg e-methanol/ton sugarcane via CO₂ hydrogenation, and 3.68 kg of biomethane/ton sugarcane from biogas upgrading. Hydrogen production through biomethane reforming and photovoltaic-powered electrolysis increases methanol output without raising emissions. The integrated system achieves energy efficiencies of up to 57.3% and enables the avoidance of up to 493 kg of CO₂/ton sugarcane over the planning horizon. When thermal integration is excluded, efficiency drops by 8% and net energy production per area falls by 11%, due to the need to divert bagasse to cogeneration. Although economic challenges remain, CO₂ remuneration ranging from USD 3.27 to USD 129.79 per ton could ensure project viability. These findings highlight the role of integrated energy systems in enabling sustainable and economically feasible sugarcane biorefineries. Full article

Under the constraints of the “dual carbon” goals, accurately depicting the full life cycle carbon footprint of green hydrogen and its derivatives and quantifying the potential for emission reduction is a prerequisite for hydrogen energy policy and investment decisions. This paper constructs a unified life cycle model, covering the entire process from “wind and solar power generation–electrolysis of water to producing hydrogen-synthesis of methanol/ammonia-terminal transportation”, and includes the manufacturing stage of key front-end equipment and the negative carbon effect of CO₂ capture within a single system boundary, and also presents an empirical analysis. The results show that the full life cycle carbon emissions of wind power hydrogen production and photovoltaic hydrogen production are 1.43 kgCO₂/kgH₂ and 3.17 kgCO₂/kgH₂, respectively, both lower than the 4.9 kg threshold for renewable hydrogen in China. Green hydrogen synthesis of methanol achieves a net negative emission of −0.83 kgCO₂/kgCH₃OH, and the emission of green hydrogen synthesis of ammonia is 0.57 kgCO₂/kgNH₃. At the same time, it is predicted that green hydrogen, green ammonia, and green methanol can contribute approximately 1766, 66.62, and 30 million tons of CO₂ emission reduction, respectively, by 2060, providing a quantitative basis for the large-scale layout and policy formulation of the hydrogen energy industry. 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

Solid oxide electrolysis (SOEL) has emerged as a promising technology for efficient hydrogen production. Its main advantages lie in the high operating temperatures, which enhance thermodynamic efficiency, and in the ability to supply part of the required energy in the form of heat. Nevertheless, improving the long-term durability of stack materials remains a key challenge. Thermal energy can be supplied by dedicated integration with different industrial processes, where the main challenge lies in the elevated stack operating temperature (700–900 °C). This review provides a comprehensive analysis of the integration of solid oxide electrolysis cells (SOECs) into different industrial applications. Main processes cover methanol production, methane production, Power-to-Hydrogen systems, or the use of reversible solid oxide electrolysis cell (rSOEC) stacks that can operate in both electrolysis and fuel cell mode. The potential of co-electrolysis to increase process flexibility and broaden application areas is also analyzed. The aim is to provide a comprehensive analysis of the integration strategies, identify the main technical and economic challenges, and highlight recent developments and future trends in the field. A detailed comparison assessment of the different processes is being discussed in terms of electrical and thermal efficiencies and operating parameters, as well as Key Performance Indicators (KPIs) for each process. Technical-economic challenges that are currently a barrier to their implementation in industry are also analyzed. Full article

Fuel cells have become a fundamental technology in the development of clean energy systems, playing a vital role in the global shift toward a low-carbon future. With the growing need for sustainable hydrogen production, perfluoro sulfonic acid (PFSA) ionomer membranes play a critical role in optimizing green hydrogen technologies and fuel cells. This study aims to investigate the effects of different environmental and solvent treatments on the chemical and physical properties of Nafion N−115 membranes to evaluate their suitability for both hydrogen production in proton exchange membrane (PEM) electrolyzers and hydrogen utilization in fuel cells, supporting integrated applications in the local and global green hydrogen economy. To achieve this, Nafion N−115 membranes were partially dissolved in various solvent mixtures, including ethanol/isopropanol (EI), isopropanol/water (IW), dimethylformamide/N-methyl-2-pyrrolidone (DN), and ethanol/methanol/isopropanol (EMI), evaluated under water immersion and thermal stress, and characterized for chemical stability, mechanical strength, water uptake, and proton conductivity using advanced electrochemical and spectroscopic techniques. The results demonstrated that the EMI-treated membrane showed the highest proton conductivity and maintained its structural integrity, making it the most promising for hydrogen electrolysis applications. Conversely, the DN-treated membrane exhibited reduced stability and lower conductivity due to solvent-induced degradation. This study highlights the potential of EMI as an optimal solvent mixture for enhancing PFSA membranes performance in green hydrogen production, contributing to the advancement of sustainable energy solutions. Full article

This work addresses for the first time the effect of anode serpentine channel depth on Methanol Electrolysis Cells (MECs) and Direct Methanol Fuel Cells (DMFCs) for improving performance of both devices. Anode plates with serpentine flow fields of 0.5 mm, 1.0 mm and 1.5 mm depths are designed and tested in single-cells to compare their behaviour. Performance was evaluated through methanol crossover, polarization and power density curves. Results suggest shallower channels enhance mass transfer efficiency reducing MEC energy consumption for hydrogen production at 40 mA∙cm⁻² by 4.2%, but increasing methanol crossover by 30.3%. The findings of this study indicate 1.0 mm is the best depth among those studied for a MEC with 16 cm² of active area, while 0.5 mm is the best for a DMFC with the same area with an increase in peak power density of 14.2%. The difference in results for both devices is attributed to higher CO₂ production in the MEC due to its higher current density operation. This increased CO₂ production alters anode two-phase flow, partially hindering the methanol oxidation reaction with shallower channels. These findings underscore the critical role of channel depth in the efficiency of both MEC and DMFC single-cells. Full article

Electrolysis of abundant seawater resources is a promising approach for hydrogen production. However, the high-concentration chloride ion in seawater readily induces the chlorine evolution reaction (CER), resulting in catalyst degradation and decreased electrolysis efficiency. In recent years, the electrooxidation of small organic molecules (e.g., methanol), biomass-derived compounds (e.g., 5-hydroxymethylfurfural), and plastic monomers (e.g., ethylene glycol) has been seen to occur at lower potentials to substitute for the traditional oxygen evolution reaction (OER) and CER. This alternative approach not only significantly reduces energy consumption for hydrogen production but also generates value-added products at the anode. This review provides a comprehensive summary of research advancements in value-added electrooxidation reaction-assisted seawater hydrogen production technologies and emphasizes the underlying principles of various reactions and catalyst design methodologies. Finally, the current challenges in this field and potential future research directions are systematically discussed. Full article

Multi-energy microgrids (MEMs) can achieve efficient and low-carbon energy utilization by relying on the coordination, complementarity, and coupling conversion of different energy sources, which is of great significance for new energy consumption and energy cascade utilization. In this paper, a low-carbon economic dispatch model of a multi-energy microgrid that uses a joint carbon capture–CHP-P2G operation is proposed. Firstly, the basic structure of the power–electrolysis–methanol energy (PEME) is established. Secondly, a flexible mechanism for the joint operation of CCPPs and CHP is analyzed, and a flexible joint operation model for carbon capture–CHP-P2G is proposed. Finally, considering the system’s low-carbon operation and economy, a low-carbon economic dispatch model for a multi-energy microgrid in a park is established, with the goal of minimizing the total operating cost of PEME in the park. The results illustrate that the introduction of a liquid storage tank reduces the total cost and carbon emissions of the MEM by 4.04% and 8.49%, respectively. The application of an electric boiler and ORC effectively alleviates the problem of peak–valley differences in the electric heating load. Our joint operation model realizes the dual optimization of the MEM’s flexibility and low-carbon requirement through the collaboration of multiple pieces of technology. Full article

The growing demand for clean energy and sustainable industrial processes has driven interest in integrated energy systems that optimize resource utilization while minimizing environmental impacts. This study presents the simulation and environmental sustainability assessment of an integrated process combining liquefied natural gas (LNG), Allam–Fetvedt cycle, solid oxide electrolysis’ system, and methanol synthesis to produce clean energy. The proposed system enhances overall efficiency and sustainability by utilizing the Allam–Fetvedt cycle to generate power while capturing CO₂, which is then used in the manufacture of syngas and hydrogen by the electrolysis of water and CO₂. Syngas is subsequently transformed into methanol, a viable alternative fuel characterized by lowcarbon emissions. A comprehensive process simulation is conducted to evaluate energy efficiency, material flows, and system performance. The sustainability assessment focuses on environmental impact indicators, including carbon footprint reduction, energy efficiency improvements, and resource optimization. The results demonstrate that the integrated system significantly reduces CO₂ emissions while maximizing energy recovery, making it a promising approach for decarbonized energy production. In this study, the integrated process including the ASU, power cycle, electrolyzers, methanol production units, and LNG unit results in carbon emissions of 0.29 kg CO₂ per kg of LNG produced, which is very close to the literature-reported lower limit, even though it also has methanol production. On the other hand, when the identical process is assessed solely for methanol production (without the LNG unit), it attains net-zero carbon emissions. Despite the incorporation of high-energy electrolyzer systems, the overall energy demand of the proposed integrated process remains comparable to that of existing conventional technologies with high emission outputs. Full article