Search Results (454)

Palmatine chloride (berbericinine, C₂₁H₂₂ClNO₄) is a protoberberine alkaloid found in several plants, including Rhizoma Coptidis, Cortex Phellodendri, Rhizoma Corydalis, Guduchi (Tinospora cordifolia), and Tinospora sagittata roots. Palmatine chloride (PA) is known as an inhibitor of dopamine generation. However, its effect on endoplasmic reticulum (ER) stress-related macrophage activation caused by endotoxin (lipopolysaccharide) is not yet well known. In this study, the effects of PA on pyroptotic responses of mouse macrophages (RAW 264.7) activated by endotoxin were investigated using Griess reagent assay for nitric oxide (NO) production, fluo-4 assay for cytosolic calcium release, dihydrorhodamine 123 assay for hydrogen peroxide production, multiple cytokine assay for cytokine production, real-time PCR for inflammatory gene transcriptions, and flow cytometry assay for p38 MAPK activation. Preliminary experiments using THP-1 human monocytic cells demonstrated that PA was not cytotoxic and significantly reduced basal NO production. Results revealed that PA significantly reduced excessive production levels of NO, hydrogen peroxide, pro-inflammatory cytokines (such as interleukin (IL)-6, CCL3 (MIP-1α), and CSF2 (GM-CSF)), and cytosolic calcium release in endotoxin-stimulated RAW 264.7, but significantly increased the production of anti-inflammatory cytokine IL-10. PA inhibited endotoxin-induced transcripts of Chop, Stat1, Fas, and c-Fos in activated RAW 264.7. It also decreased p38 MAPK phosphorylation and level of Fas in RAW 264.7 stimulated by endotoxin. To further interpret these findings, a network pharmacology-informed analysis based on large-scale literature mining was performed, supporting the multi-target regulatory role of PA in ER stress-related pathways. Briefly, PA exerts anti-inflammatory effects on endotoxin-stimulated RAW 264.7 via the calcium-CHOP pathway, consequently reducing endotoxin-induced production of pro-inflammatory mediators (NO, cytokines, etc.) and relieving ER stress-related pyroptotic cascade. Full article

Environmental policies and intermittent renewable energy (RE) drive large-scale hydrogen production towards hybrid supply configurations, combining collocated RE units and the electricity market (EM). This links the power and hydrogen sectors through EM/hydrogen prices, dispatch, and hydrogen demand profiles. In a hybrid configuration, the strategic role of RE in the EM enhances these links by creating profit opportunities. This work develops a bi-level model, optimizing electrolyzer size and location, operational decisions and RES bidding strategies, while explicitly modeling EM clearing. In the upper-level, an EM player, owning strategically bidding RE assets, evaluates expanding into the use of electrolyzers that act as price-takers. The lower-level problem clears the EM. The proposed framework is applied to an IEEE 24-node test system. The results show how EM conditions determine investments for different hydrogen price cases. It is revealed that differentiated electricity sourcing across electrolyzers and efficiency-preserving dispatch impact operational decisions, leading to revenue improvements. Moreover, renewable capacity withholding is used to avoid zero EM prices and mitigate the economic impact of unmet hydrogen demand when RE availability is limited and electrolyzer participation in the EM is restricted. Time-window-constrained hydrogen demand mitigates unutilized RE by 39% compared to that for hourly demand. Full article

Green hydrogen—hydrogen produced from renewable electricity—is central to global decarbonization strategies. However, despite their fragile governance, damaged infrastructure, water scarcity, and limited investment security, conflict-affected developing economies remain largely absent from hydrogen research. This study addresses that gap by developing and validating a multi-evidence strategic framework for green-hydrogen (GH₂) adoption in fragile institutional environments, using Palestine as a challenging test case. Methodologically speaking, the framework integrates four evidence streams—barrier prioritization by 45 Palestinian experts using the Analytic Hierarchy Process (AHP); structural modeling of barrier–adoption–sustainability relationships using partial least squares structural equation modeling (PLS-SEM); strategic-pathway ranking using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS); and an original Sustainable Development Goal (SDG) Contribution Index—externally validated by an independent panel of 120 energy experts across 18 Middle East and North Africa (MENA) countries. Three findings stand out. Firstly, expert perception and structural evidence diverge: technical barriers receive the highest expert weight (56.2%) yet show the weakest structural effect on adoption (β = −0.230), whereas social barriers, weighted lowest by experts (4.8%), rank second in predictive power (β = −0.310). Secondly, Small-Scale Community Production is the most robust deployment pathway, ranked first under every weighting scenario tested. Thirdly, government policy quality acts as a governance multiplier, raising the sustainability returns of adoption by 20.2%, with benefits concentrated in SDGs 7, 13, 8, and 9. Practically speaking, the framework yields seven strategic goals and a phased 2026–2040 roadmap for fragile developing economies. Full article

The growing demand for sustainable energy carriers has intensified interest in hydrogen production from renewable resources and waste-derived substrates. In this context, microbial electrolysis cells (MECs) have emerged as a promising technology for the simultaneous treatment of organic waste and biohydrogen generation. This review provides an overview of recent advances in MEC systems, focusing on reactor configurations, performance indicators such as hydrogen production rate, coulombic efficiency, and chemical oxygen demand removal. Attention is given to the valorization of real waste streams, including municipal and agro-industrial effluents, highlighting the differences between laboratory- and pilot-scale applications. While numerous studies have demonstrated the technical feasibility of MECs, several bottlenecks still limit their large-scale implementation, including challenges associated with the use of complex substrates. In particular, untreated wastewater often leads to reduced process efficiency due to its variable composition and the occurrence of competing microbial pathways. To overcome these limitations, integrated approaches are also discussed, with emphasis on the coupling of dark fermentation, capable of enhancing substrate biodegradability through the production of volatile fatty acids, with MEC systems. Overall, MEC technology represents a promising pathway for sustainable hydrogen production within circular waste management frameworks, although further advancements are required to enable its practical application. Full article

Green hydrogen is increasingly discussed as an energy carrier that can link electricity, gas, heat, and transport sectors. However, many existing reviews address this topic from separate viewpoints, such as hydrogen production technologies, Artificial Intelligence (AI) applications, or system integration, with less attention to how policy and market conditions affect deployment. This review brings these related aspects together in one structured discussion. The paper first reviews the hydrogen supply chain, including production, storage, transport, and utilization. It then discusses an integrated multi-energy architecture in which hydrogen interacts with electricity, natural gas, heat, and cooling networks. Policy instruments in five major economies, including the European Union, the United States, China, Japan, and India, are compared. The review also summarizes the main barriers to large-scale deployment, including high production costs, limited infrastructure, technological challenges, regulatory uncertainty, and supply-chain constraints. In addition, the current market structure and selected large-scale hydrogen projects planned in the United States are reviewed. The paper also examines the role of artificial intelligence in green hydrogen systems. AI applications are grouped into four main stages of the hydrogen value chain: forecasting renewable energy generation, improving electrolyzer design and operation, optimizing storage and distribution, and supporting system-level techno-economic assessment. Recent Machine Learning (ML) studies are compared based on their methods and their contributions to operation and planning. Overall, this review highlights the role of AI in enabling green hydrogen integration within multi-energy systems. Full article

Green ammonia systems provide an important pathway for converting fluctuating renewable electricity into transportable chemical products. To address the coupled challenges of renewable power variability, heterogeneous electrolyzer dynamics, hydrogen storage constraints, and continuous ammonia synthesis under weak-grid conditions, this paper develops a mixed-integer linear programming scheduling model considering the coordination and start–stop characteristics of ALK–PEM hybrid electrolyzers. The model uses a 15 min resolution over a two-day horizon and integrates renewable power supply, grid electricity purchase, electrolysis, hydrogen storage, and flexible ammonia synthesis in a unified framework. The off, hot-standby, and running states of ALK and PEM electrolyzers are explicitly represented. The case results show that, under the high-renewable-resource scenario, ammonia production reaches 494.93 t, with a curtailment ratio of 3.23% and a grid electricity share of 0.68%, indicating strong renewable-energy conversion capability. Under the low-renewable-resource scenario, ammonia production decreases to 180.09 t and the grid electricity share increases to 40%, showing that the operating priority shifts to maintaining continuous production and safe hydrogen inventory. The ALK hydrogen production share decreases from 93.96% in the high-resource scenario to 75.66% in the low-resource scenario, while the PEM share increases from 6.04% to 24.34%. This indicates that ALK mainly supports large-scale base-load hydrogen production under abundant renewable resources, whereas PEM provides fast compensation and marginal regulation when renewable resources are limited and more volatile. The results demonstrate that ALK base-load production, PEM fast regulation, hydrogen storage buffering, and platform-like flexible ammonia operation jointly provide the main flexibility sources in the studied weak-grid green ammonia system. Full article

Alkaline water electrolysis has become a major technology for large-scale photovoltaic (PV) hydrogen production due to its maturity and low cost. However, PV power fluctuations can cause short-term load imbalances and long-term degradation imbalances in alkaline water electrolyzer (AWE) clusters. To address this problem, this paper proposes an adaptive rotation operation strategy based on a composite degradation model. The model considers energy throughput, hot starts, cold starts, and low-load operation to characterize the relative degradation stress of AWEs under fluctuating PV input. Based on this model, virtual rotation is first used to redistribute power among online AWEs, while physical rotation is performed when necessary according to optimal start–stop decisions. A PV hydrogen production experimental platform is built to verify the feasibility of power redistribution, physical rotation, and load balancing. The measured PV power curve is further used for simulation–experiment comparison, and the results show that the model can capture the main operating process of the PV hydrogen production system. Large-scale simulation results show that, compared with S1, S2, and S4, the proposed strategy increases PV utilization by 8.13%, 4.91%, and 2.85%, improves system efficiency by 5.42%, 3.10%, and 1.56%, reduces start–stop cycles by 12.16%, 8.49%, and 3.39%, reduces the average composite degradation index by 29.4%, 21.4%, and 10.1%, and reduces the composite degradation imbalance index by 56.9%, 40.4%, and 22.2%, respectively. The proposed strategy can improve PV utilization and system efficiency while reducing start–stop frequency and degradation imbalances among AWEs. Full article

The transition toward low-carbon energy systems has intensified interest in sustainable hydrogen production technologies. One of the most promising methods for producing green hydrogen is water electrolysis powered by renewable energy. This work reviews recent advances in electrode materials used in four major electrolysis technologies: alkaline (ALK), proton exchange membrane (PEM), solid oxide electrolysis cells (SOEC), and anion exchange membrane (AEM). A bibliometric analysis of scientific publications from 2021 to 2025 highlights the rapid growth of research and the increasing importance of electrode materials in improving electrolysis performance. Operating environments, material requirements, and catalytic properties are compared across these systems. Recent developments in electrocatalysts—including transition-metal alloys, heterostructured catalysts, defect-engineered materials, and nanostructured systems—are evaluated in terms of catalytic activity, durability, and scalability. Particular attention is given to reducing noble metal usage while maintaining high electrochemical performance. Results indicate that transition-metal-based catalysts and engineered interfaces can achieve activity comparable to noble-metal systems while offering better cost efficiency. However, challenges related to long-term durability, large-scale synthesis, and standardized testing persist. Continued interdisciplinary research in materials design and electrochemical engineering is essential to enable efficient, durable, and cost-effective green hydrogen production. Full article

Namibia’s vast renewable energy potential positions it as a strategic location for green hydrogen production, a key vector in advancing global decarbonization objectives. Nevertheless, identifying optimal production sites remains a complex and multidimensional challenge. This study presents a comprehensive techno-economic and spatial assessment to determine the most suitable areas for large-scale green hydrogen production in Lüderitz, Namibia. The analysis employs the Analytic Hierarchy Process integrated with Geographic Information System techniques to evaluate and spatially prioritize potential sites. Critical criteria, including solar irradiance, wind velocity, land use, and proximity to essential infrastructure, were systematically weighted and overlayed to generate suitability classifications. The results indicate that approximately 20% of the study area exhibits high suitability, 68% exhibits moderate suitability, 8% exhibits marginal suitability, and 4% is unsuitable for the development of integrated wind and solar energy. These findings provide a robust scientific basis for guiding policy formulation, investment planning, and the spatial optimization of Namibia’s emerging green hydrogen industry. Full article

As Sweden advances toward large-scale hydrogen production for industrial applications, low-grade waste heat (≈80 °C) from electrolyzers becomes available. A proposed solution is to integrate this heat between the two condensers in a combined heat and power plant. This can be done with different configurations, which were setup and studied. At full load, introducing 15 MW of heat increased electrical power output and cycle efficiency by up to 169 kW and 0.173% points, respectively. The same configuration under part-load showed the best improvement up to 11 MW of added heat, providing up to 302 kW in power output compared to the reference part-load case without waste heat. At a further increase in heat input at part-load, the best configuration shifted. At 15 MW of heat input, the best case resulted in a 393 kW reduction in electric output relative to the reference case. This is still significantly better than using a heat pump, which would require up to 1.43 MW for the same heat utilization. The results show that direct integration of electrolyzer waste heat into CHP plants can enhance electrical efficiency and power output without increasing electricity consumption, offering a viable and relatively simple alternative to heat pump-based solutions in district heating systems. Full article

The main challenge of hydrogen electrolysis lies in the high cost of hydrogen production. Achieving a decarbonized energy sector requires substantial investment to shift from carbon-intensive technologies to more sustainable alternatives. However, investment decisions in this context remain complex and uncertain. Currently, green hydrogen projects account for more than 500 initiatives worldwide and are expected to expand rapidly in the coming years. Evidence from feasibility studies suggests that green hydrogen produced from renewable energy is already technically viable and is approaching economic competitiveness. The current emphasis is on large-scale deployment and learning-by-doing processes to reduce electrolyzer costs and improve supply chain efficiency. This transition requires appropriate funding mechanisms, often involving significant public sector participation alongside private investment. This study analyzes the financing structures of green hydrogen projects in Germany, Australia, and Brazil using Principal Component Analysis (PCA) to identify the most relevant combinations of technical, economic, and financial variables. Unlike previous studies that address technical, economic, and financial dimensions in isolation, this study offers an integrated, empirically grounded analysis at the project level, combining cross-country comparison with a multivariate approach. The results indicate that project characteristics are strongly associated with capital intensity and financing structures, while cost variables such as levelized cost of hydrogen (LCOH) play a secondary role in explaining variation across projects. These findings suggest that financing arrangements—particularly those involving public support mechanisms—are closely associated with project configuration in this emerging sector. However, these results should be interpreted as patterns of statistical association rather than evidence of causal relationships. Overall, the analysis highlights the importance of coordinated financing strategies in supporting the development of green hydrogen and its potential contribution to emissions reduction in line with the Paris Agreement and the transition toward climate neutrality. Full article

Hydrogen energy is an important carrier for achieving China’s “dual carbon” goals, and one of the sources of green hydrogen is to develop better water electrolysis catalysts. This paper reviews the current research status of water electrolysis hydrogen production catalysts, analyzes the role and significance of advanced hydrogen energy catalysts in achieving the “dual carbon” goals, and conducts an in-depth analysis of the difficulties in moving from the laboratory to large-scale application, namely, how to bridge the “four gaps”, including catalyst performance evaluation, long-term application of catalysts, macro-scale preparation, and device integration. It also proposes overall improvement ideas and measures. In this paper, effective improvement methods are proposed for these “four gaps”, which can improve the relevant indicators and service life of water electrolysis hydrogen production catalysts, further promote the large-scale production and industrial application of green hydrogen, and provide a strong guarantee for solving China’s “dual carbon” problems. Full article

Given the large natural gas (NG) reserves of the Intermountain West (I-WEST) region in the USA, it can emerge as a leader in hydrogen (H₂) production. Currently, H₂ production via steam methane reforming (SMR) of NG releases carbon dioxide (CO₂) and the natural gas infrastructure has fugitive NG and H₂ losses during production, conversion and transportation. Integrated carbon capture and sequestration (CCS) is a promising approach for producing hydrogen and CO₂ from the SMR process for industrial uses including power, chemicals and fuels. However, the NG losses and regional water availability can be limiting factors for H₂ production. H₂ production assessments are often made at the global scale and neglect regional factors such as abundant gas and limited water in the I-WEST. We demonstrate that a regional SMR process unit sitting near NG wells offers opportunities to significantly reduce fugitive NG losses. We show that regional H₂ production by SMR has a lower emissions profile than widespread natural gas combustion in the I-WEST and reduces the H₂ production cost as well. Replacing the I-WEST transportation sector with H₂ fuel cell vehicles and using 100% H₂-powered electricity can provide substantial reductions in water consumption and fuel costs. This is better than blending H₂ with NG which is more expensive. The captured CO₂ can be effectively used for enhanced oil recovery in I-WEST. Finally, the potential of utilizing produced, brackish and treated impaired water sources is assessed to meet the water needs for H₂ production in the I-WEST. Full article

Large-scale hydrogen storage is expected to play a critical role in balancing the variability of renewable energy systems, particularly those driven by wind power. However, the combined influence of storage capacity and deliverability on supply reliability remains insufficiently characterized. This study investigates the reliability limits of hydrogen storage systems operating under variable hydrogen production and time-varying demand. A dimensionless modeling framework is developed to map system performance across a wide range of storage capacities and deliverability levels. The results reveal a clear transition between reliable and unreliable operating regimes. Reliable operation requires a minimum deliverability level approximately equal to the mean hydrogen production rate, corresponding to a value of about 1.05–1.10 times the average production across the range of intermittency conditions considered in this study (from moderate to highly variable production). Below this threshold, increasing storage capacity alone cannot prevent supply shortfalls. Once this threshold is exceeded, further increases in deliverability provide diminishing returns and storage capacity becomes the dominant factor governing reliability. In this regime, the required storage capacity approaches a plateau on the order of 10–30 days of average hydrogen throughput, depending on the level of production variability. The proposed regime-based framework provides a practical tool for evaluating storage feasibility and guiding preliminary capacity design in renewable hydrogen systems. Full article

Electrochemical water splitting for hydrogen production is a key technological route toward the large-scale generation of green hydrogen. However, the anodic oxygen evolution reaction (OER) suffers from sluggish kinetics and high overpotential, necessitating the development of non-noble metal catalysts that simultaneously possess low cost, high activity, and excellent stability. In this work, a nitrogen-doped graphene quantum dots@nickel–iron layered double hydroxide (N-GQDs@NiFe-LDH) composite catalyst was in situ constructed via a facile hydrothermal strategy. Benefiting from the electronic modulation and structural confinement effects of N-GQDs, the intrinsic catalytic activity and structural stability of the catalyst were simultaneously enhanced. The as-prepared catalyst requires an overpotential of only 320 mV to deliver a current density of 500 mA cm⁻² and maintains 98% of its initial activity after 100 h of chronoamperometric stability testing, demonstrating promising potential for practical applications. Multiscale characterizations revealed that N-GQDs formed strong electronic interactions with Ni/Fe active sites at the interface, significantly enhanced interfacial electron transport, and accelerated the OER kinetics. This study demonstrates that the N-GQDs@NiFe-LDH catalytic system constructed via an interfacial heterostructure engineering strategy provides a new insight for the rational design and development of efficient non-noble-metal OER electrocatalysts. Full article