Production & Supply Chain

This research aimed to perform an in-depth comparative analysis of MCDM methods utilizing ArcGIS Pro 3.0.2 to identify the most suitable sites for wind-powered hydrogen production plants in Erbil Governorate Iraq. VIKOR TOPSIS SAW and Weighted Overlay techniques were implemented and applied to evaluate various criteria. A comparative analysis determined that VIKOR had the highest consistency and robustness making it the most suitable approach for selecting a site for windpowered hydrogen facilities. Spatial analysis showed that the southern and southwestern regions of Erbil Governorate were the most favourable areas for hydrogen generation. Wind turbine technical feasibility assessments identified the E112/4500 and V126e3.45 turbine models as the most efficient for these regions with high annual hydrogen production. The spatial configuration including the optimal turbine spacing had a significant effect on the capacity and production potential. ArcPro integration with MCDM significantly enhanced spatial analysis providing high-resolution data processing and advanced visualization capabilities.

Photocatalytic water splitting and organic reforming based on nano-sized composites are gaining increasing interest due to the possibility of generating hydrogen by employing solar energy with low environmental impact. Although great efforts in developing materials ensuring high specific photoactivity have been recently recorded in the literature survey the solar-to-hydrogen energy conversion efficiencies are currently still far from meeting the minimum requirements for real solar applications. This review aims at reporting the most significant results recently collected in the field of hydrogen generation through photocatalytic water splitting and organic reforming with specific focus on metal-based semiconductor nanomaterials (e.g. metal oxides metal (oxy)nitrides and metal (oxy)sulfides) used as photocatalysts under UVA or visible light irradiation. Recent developments for improving the photoefficiency for hydrogen generation of most used metal-based composites are pointed out. The main synthesis and operating variables affecting photocatalytic water splitting and organic reforming over metal-based nanocomposites are critically evaluated.

Water photoelectrolysis cells based on photoelectrochemical water splitting seem to be an interesting alternative to other traditional green hydrogen generation processes (e.g. water electrolysis). Unfortunately the practical application of this technology is currently hindered by several difficulties: low solar-to-hydrogen (STH) efficiency expensive electrode materials etc. A novel concept based on a tandem photoelectrolysis cell configuration with an anion-conducting membrane separating the photoanode from the photocathode has already been proposed in the literature. This approach allows the use of low-cost metal oxide electrodes and nickel-based co-catalysts. In this paper we conducted a study to evaluate the economic and environmental sustainability of this technology using the environmental life cycle cost. Preliminary results have revealed two main interesting aspects: the negligible percentage of externalities in the total cost.

Hydrogen production from gasification of biowaste generates large volumes of CO2 due to endothermic biowaste decomposition. Alternatively the Sun can provide that energy. To evaluate the yield and performance of solarbased gasifiers at country scale a multi-scale approach is required. First the operation of a solar gasifier is analyzed by developing a two-phase model validated and scaled to industrial level. Next the performance and yield of such technology as a function of the radiation received is studied taking Spain as a case study. The results were promising obtaining a syngas rich in H2. However tar and char were not reduced due to insufficient temperature. Scale-up studies revealed energy losses to the environment in the industrial-scale gasifier which suggested the use of segmented heating. In turn diameters no larger than 0.8 m and biomass feeding rates below 0.85 kg/s highlight the deployment of a modular design due to particle size limitations. Finally the large-scale waste valorization showed that the gasifier can only operate in Spain in the summer months. It can run over 180 h/month and more than 250 days/year only in C´ adiz and Santa Cruz de Tenerife which also showed the highest yearly production capacities.

Proton exchange membrane water electrolyzers (PEMWEs) are a promising technology for large-scale hydrogen production yet their industrial deployment is hindered by the harsh acidic conditions and sluggish oxygen evolution reaction (OER) kinetics. This review provides a comprehensive analysis of recent advances in iridium-based electrocatalysts (IBEs) emphasizing novel optimization strategies to enhance both catalytic activity and durability. Specifically we critically examine the mechanistic insights into OER under acidic conditions revealing key degradation pathways of Ir species. We further highlight innovative approaches for IBE design including (i) morphology and support engineering to improve stability (ii) structure and phase modulation to enhance catalytic efficiency and (iii) electronic structure tuning for optimizing interactions with reaction intermediates. Additionally we assess emerging electrode engineering strategies and explore the potential of non-precious metal-based alternatives. Finally we propose future research directions focusing on rational catalyst design mechanistic clarity and scalable fabrication for industrial applications. By integrating these insights this review provides a strategic framework for advancing PEMWE technology through highly efficient and durable OER catalysts.

Hydrogen production from water electrolysis can not only reduce greenhouse gas emissions but also has abundant raw materials which is one of the ideal ways to produce hydrogen from new energy. The hydrogen production power supply is the core component of the new energy electrolytic water hydrogen production device and its characteristics have a significant impact on the efficiency and purity of hydrogen production and the service life of the electrolytic cell. In essence the DC/DC converter provides the large current required for hydrogen production. For the converter its input still needs the support of a DC power supply. Given the maturity and technical characteristics of new energy power generation integrating energy storage into offshore energy systems enables stable power supply. This configuration not only mitigates energy fluctuations from renewable sources but also further reduces electrolysis costs providing a feasible pathway for large-scale commercialization of green hydrogen production. First this paper performs a simulation analysis on the wind–solar hybrid energy storage power generation system to demonstrate that the wind–solar–storage system can provide stable power support. It places particular emphasis on the significance of hydrogen production power supply design—this focus stems primarily from the fact that electrolyzers impose specific requirements on high operating current levels and low current ripple which exert a direct impact on the electrolyzer’s service life hydrogen production efficiency and operational safety. To suppress the current ripple induced by high switching frequency and high output current traditional approaches typically involve increasing the output inductor. However this method substantially increases the volume and weight of the device reduces the rate of current change and ultimately results in a degradation of the system’s dynamic response performance. To this end this paper focuses on developing a virtual impedance control technology aiming to reduce the ripple amplitude while avoiding an increase in the filter inductor. Owing to constraints in current experimental conditions this research temporarily relies on simulation data. Specifically a programmable power supply is employed to simulate the voltage output of the wind–solar–storage hybrid system thereby bringing the simulation as close as possible to the actual operating conditions of the wind–solar–storage hydrogen production system. The experimental results demonstrate that the proposed method can effectively suppress the ripple amplitude maintain high operating efficiency and ultimately meet the expected research objectives. That makes it particularly suitable as a high-quality power supply for offshore hydrogen production systems that have strict requirements on volume and weight.

Hydrogen as a clean energy source has enormous potential in addressing global climate change and energy security challenges. This paper discusses different hydrogen production methodologies (steam methane reforming and water electrolysis) focusing on the electrolysis process as the most promising method for industrial-scale hydrogen generation. The review delved into three main electrolysis methods including alkaline water electrolysis proton exchange membrane electrolysis and anion exchange membrane electrolysis cells. Also the production of hydrogen as a by-product by means of membrane cells and mercury cells. The process of reforming natural gas (mainly methane) using steam is currently the predominant technique comprising approximately 96% of the world’s hydrogen synthesis. However it is carbon intensive and therefore not sustainable over time. Water as a renewable resource carbon-free and rich in hydrogen (11.11%) offers one of the best solutions to replace hydrogen production from fossil fuels by decomposing water. This article highlights the fundamental principles of electrolysis recent membrane studies and operating parameters for hydrogen production. The study also shows the amount of pollutant emissions (g of CO2/g of H2) associated with a hydrogen color attribute. The integration of water electrolysis with renewable energy sources constitutes an efficient and sustainable strategy in the production of green hydrogen minimizing environmental impact and optimizing the use of clean energy resources.

Life Cycle Assessments (LCAs) are predominantly conducted using a static approach which aggregates emissions over time without considering emissions timing. Additionally LCAs often assume biogenic carbon neutrality neglecting site-specific forest carbon fluxes and temporal trade-offs. This study applies both static and dynamic LCA and incorporates biogenic carbon to evaluate the climate change impact of hydrogen production. It focuses on gasification of eucalyptus woodchips cultivated on former marginal grasslands (BIO system) which avoids competition with land used for food production. A case study is presented in western Andalusia (Spain) with the aim to replace hydrogen produced via the conventional steam methane reforming (SMR) pathway (BAU system) at La Rabida ´ refinery. The CO2FIX model was used to simulate biogenic carbon fluxes providing insights into carbon sequestration dynamics and it was found that the inclusion of biogenic carbon flows from eucalyptus plantations dramatically reduced CO₂ equivalent emissions (176 % in the static approach and 369 % in the dynamic approach) primarily due to soil and belowground biomass carbon sequestration. The dynamic LCA showed significantly lower CO₂ emissions than the static LCA (106 % reduction) shifting emissions from − 1.79 kg CO₂/kg H₂ in the static approach to − 3.69 kg CO₂/kg H₂ in the dynamic approach. These findings highlight the need to integrate emission dynamics and biogenic carbon flows into LCA methodologies to support informed decision-making and the development of more effective environmental policies.

Green hydrogen is emerging as a pivotal energy carrier in the global transition toward decarbonization offering a sustainable alternative to fossil fuels in sectors such as heavy industry transportation power generation and long-duration energy storage. Despite its potential large-scale deployment remains hindered by significant economic technological and infrastructure challenges. Current production costs for green hydrogen range from USD 3.8 to 11.9/kg H2 significantly higher than gray hydrogen at USD 1.5–6.4/kg H2 due to high electricity prices and electrolyzer capital costs exceeding USD 2000 per kW. This review critically examines the key bottlenecks in green hydrogen production focusing on water electrolysis technologies electrocatalyst limitations and integration with renewable energy sources. The economic viability of green hydrogen is constrained by high electricity consumption capital-intensive electrolyzer costs and operational inefficiencies making it uncompetitive with fossil fuel-based hydrogen. Infrastructure and supply chain challenges including limited hydrogen storage transport complexities and critical material dependencies further restrict market scalability. Additionally policy and regulatory gaps disparities in financial incentives and the absence of a standardized certification framework hinder international trade and investment in green hydrogen projects. This review also highlights market trends and global initiatives assessing the role of government incentives and cross-border collaborations in accelerating hydrogen adoption. While technological advancements and cost reductions are progressing overcoming these challenges requires sustained innovation stronger policy interventions and coordinated efforts to develop a resilient scalable and cost-competitive green hydrogen sector.

Hybrid water electrolysis system was designed by using Ruthenium-Tin Oxide (RuSn12.4O2) electrocatalyst as anode material for efficient hydrogen production enhancing energy conversion efficiency. The RuSn12.4O2 Electrocatalyst was synthesized by hydrothermal method and exhibited exceptional activity making it an optimal choice for Iodide oxidation reaction (IOR) and enabling energy-saving hydrogen production. The two-electrode acidic electrolyzer reduced voltage consumption by 0.51 V at 10 mA cm-2 compared to oxygen evolution reaction (OER) at the same current density. This hybrid electrolysis system achieved a remarkable reduction in energy consumption of over 40 % compared to OER process. The Chrono-potentiometric test demonstrated that the RuSn12.4O2 electro-catalyst’s superior stability and low overpotential increase of 70 mV at 10 mAcm-2 . The RuSn12.4O2 electro-catalyst Tafel slope is also a crucial metric for understanding kinetic characteristics in both IOR and OER processes. Thus RuSn12.4O2 electro-catalyst in IOR has a lower Tafel slope (61 mV dec-1) than that in OER according to the Tafel slopes determined from linear sweep voltammetry (LSV) curves. Additionally at various potentials the electro-catalyst's activity toward IOR to produce hydrogen demonstrated exceptional performance in this electrolysis system without causing any catalyst degradation.