Production & Supply Chain

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.

Clean hydrogen (H2) is highly desirable for the sustainable development of society in the era of carbon neutrality. However the current capability of water electrolysis and steam methane (CH4) reforming to produce green and blue H2 is very limited mainly due to the high production cost difficult scale-up technology or operational risk. Here we propose the direct catalytic decomposition of diesel using a nano-Fe-based catalyst to produce the so-called ‘‘jadeite H2” while simultaneously fixing the carbon from the diesel in the form of carbon nanotubes (CNTs). Efforts are made to understand the suppression mechanism of the CH4 byproduct such as by tuning the catalyst type space velocity and reaction time. The optimal green index (GI)—that is the molar ratio of H2/carbon in a gaseous state—of the proposed technology exceeds 42 which is far higher than those of any previously reported chemical vapor deposition (CVD) method. Moreover the carbon footprint (CFP) of the proposed technology is far lower than those of grey H2 blue H2 and other dehydrogenation technologies. Compared with most of the technologies mentioned above the energy consumption (per mole of H2) and reactor amplification of the proposed technology validate its high efficiency and great practical feasibility.

This study presents an experimental approach to modelling PEM electrolysers for green hydrogen production using solar energy. The objective is to implement a temperature steady-state electrolyser model to assess the optimal coupling configuration with a photovoltaic plant and estimate the yearly hydrogen production capacity. The research focuses on the energy consumption of ancillary systems under different load conditions developing a steady-state operational model that improves hydrogen production predictions by accounting for these consumptions. The model based on polynomial equations captures the non-linear variation in energy costs under partial load conditions. PEM electrolysers produce hydrogen above 3.0 quality (99.9% purity) and it is feasible to integrate purification processes to reach 5.0 quality (99.999% purity). While small-scale systems include purification large-scale facilities separate it enabling process optimisation. Two models are introduced to estimate hydrogen mass flow depending on purity: a base-purity model and a high-purity model that includes drying and pressure swing adsorption. Both are based on experimental data from a five-year-old small-scale electrolyser and are applicable to large-scale systems at partial load. Due to test conditions the model applied to large-scale facilities underestimates hydrogen production affected by energy losses from a non-optimised purification process and electrolyser degradation. Model validation with large-scale operational data from the literature shows the model captures plant behaviour well despite the consistent underestimation described above. The model is applied to several European locations to identify optimal photovoltaic-to-electrolyser ratios. Oversizing factors between 1.4 and 2 are needed to cover ancillary consumption. The levelised cost remains comparable for both purity levels despite higher energy demands for high-purity hydrogen due to the greater cost of the electrolyser over the photovoltaic plant.

The United Nations has set a global vision towards emissions reduction and green growth through the Sustainable Development Goals (SDGs). Towards the realisation of SDGS 7 9 and 13 we focus on green hydrogen production as a potential pathway to achievement. Green hydrogen produced via water electrolysis powered by renewable energy sources represents a pivotal solution towards climate change mitigation. Energy access in West Africa remains a challenge and dependency on fossil fuels persists. So green hydrogen offers an opportunity to harness abundant solar resources reduce carbon emissions and foster economic development. This study evaluates the techno-economic feasibility of green hydrogen production in five West African countries: Ghana Nigeria Mali Niger and Senegal. The analyses cover the solar energy potential hydrogen production capacities and economic viability using the Levelised Cost of Hydrogen (LCOH) and Net Present Value (NPV). Results indicate substantial annual hydrogen production potential with LCOH values competitive with global benchmarks amidst the EU’s Carbon Border Adjustment Mechanism (CBAM). Despite this potential several barriers exist including high initial capital costs policy and regulatory gaps limited technical capacity and water resource constraints. We recommend targeted strategies for strengthening policy frameworks fostering international partnerships enhancing regional infrastructure integration and investing in capacity-building initiatives. By addressing these barriers West Africa can be a key player in the global green hydrogen market.

This study evaluates the performance of three anion-exchange membranes (FAS-50 AMX Fujifilm-AEM) and a diaphragm separator (Zirfon® UTP 500) in alkaline water sono-electrolysis using a 25 % KOH electrolyte at ambient temperature. Energy efficiency hydrogen production kinetics and membrane stability were assessed experimentally and through modeling. Among the tested separators Zirfon achieved the highest energy efficiency outperforming AEM AMX and FAS-50. Hydrogen production rates under silent conditions ranged from 2.55 µg/s (AEM) to 2.92 µg/s (FAS-50) while sonication (40 kHz 60 W) increased rates by 0.03–0.12 µg/s with the strongest relative effect observed for FAS-50 (≈4.0 % increase). By contrast Zirfon and AEM showed slight efficiency reductions (0.5–2 %) under ultrasound due to their higher structural resistance. Ion-exchange capacity tests confirmed significant degradation of polymeric membranes (IEC losses of 60–90 %) while Zirfon maintained stability in 25 % KOH. Modeling results showed that the diaphragm resistance was dominated by the ohmic losses (55–86 %) with ultrasound reducing bubble coverage and associated resistance only marginally (<0.02 V). Overall Zirfon demonstrated superior stability and efficiency for long-term operation while ultrasound primarily enhanced hydrogen evolution kinetics in mechanically weaker polymeric membranes.

This study investigates an integrated solar-powered system for wastewater treatment and hydrogen production combining solar PV a humidification–dehumidification (HDH) system solar thermal collectors and electrolysis. The objective is to evaluate the feasibility of utilizing industrial wastewater for both clean water production and green hydrogen generation. A transient analysis is conducted using TRNSYS and EES software modeling a system designed to process 4000 kg of wastewater daily. The results indicate that the HDH system produces 300 kg of clean water per hour while the electrolyzer generates approximately 66.5 kg of hydrogen per hour. The solar PV system operates under the weather conditions of Kohat Pakistan. This integrated approach demonstrates significant potential for sustainable wastewater treatment and renewable energy production offering a promising solution for industrial applications.

High‐entropy amorphous catalysts (HEACs) integrate multielement synergy with structural disorder making them promising candidates for water splitting. Their distinctive features—including flexible coordination environments tunable electronic structures abundant unsaturated active sites and dynamic structural reassembly—collectively enhance electrochemical activity and durability under operating conditions. This review summarizes recent advances in HEACs for hydrogen evolution oxygen evolution and overall water splitting highlighting their disorder-driven advantages over crystalline counterparts. Catalytic performance benchmarks are presented and mechanistic insights are discussed focusing on how multimetallic synergy amorphization effect and in‐situ reconstruction cooperatively regulate reaction pathways. These insights provide guidance for the rational design of next‐generation amorphous high‐entropy electrocatalysts with improved efficiency and durability.

This study presents an innovative approach to the production of hydrogen from liquids following hydrothermal treatment of biowaste offering a potential solution for renewable energy generation and waste management. By combining biological and hydrothermal processes the efficiency of H2 production can be significantly improved contributing to a reduced carbon footprint and lower reliance on fossil fuels. The inoculum used was fermented sludge from a wastewater treatment plant which had been thermally pretreated to enhance microbial activity towards hydrogen production. Kitchen waste consisting mainly of plant-derived materials (vegetable matter) was used as a substrate. The process was conducted in batch 1-L bioreactors. The results showed that higher pretreatment temperatures (up to 180 ◦C) increased the hydrolysis of compounds and enhanced H2 production. However temperatures above 180 ◦C resulted in the formation of toxic compounds such as catechol and hydroquinone which inhibited H2 production. The highest hydrogen production was achieved at 180 ◦C (approximately 66 mL H2/gTVSKW). The standard Gompertz model was applied to describe the process kinetics and demonstrated an excellent fit with the experimental data (R2 = 0.99) confirming the model’s suitability for optimizing H2 production. This work highlights the potential of combining hydrothermal and biological processes to contribute to the development of sustainable energy systems within the circular economy.

This study presents a comprehensive framework that integrates high-resolution energy forecasting and technoeconomic modeling to assess green hydrogen production potential in Flanders Belgium. Using 15-min interval data from the Elia Group four deep learning models (LSTM BiLSTM GRU and CNN-LSTM) were developed to forecast regional photovoltaic (PV) and onshore wind energy generation. These forecasts informed the estimation of hydrogen yields and the evaluation of the levelized cost of hydrogen (LCOH) under different configurations. Results show that wind-powered hydrogen production achieves the lowest LCOH (6.63 €/kg) due to higher annual operating hours. Among electrolysis technologies alkaline electrolysis (AEL) offers the lowest cost while proton exchange membrane (PEMEL) provides greater flexibility for intermittent power sources. The hybrid PVwind system demonstrated seasonal complementarity increasing annual hydrogen yield and improving production stability. The proposed framework supports regional planning and highlights strategic investment opportunities for cost-effective green hydrogen deployment.

A potential strategy to promote the use of clean energy is the development of catalyst-coated cathodic electrodes that are economical effective and sustainable to enhance the generation of hydrogen (H2) through the electrolysis process. This study investigates the unique design and use of stainless steel (SS) coated with a CuNiZnFeOx catalyst as both anode and cathode electrodes in the alkaline electrolysis process. The electrode exhibits an improved electrochemical behavior achieving a current density of 92 mA/cm2 at an applied voltage of 2.5 V with a surface area of 36 cm2 in 1 M KOH electrolyte at 25 ◦C. Furthermore the H2 production is systematically investigated by varying electrolyte concentration applied voltage and temperature. The results demonstrate that H2 production increases significantly with enhanced electrolyte concentration (3102 mL at 2 M KOH) applied voltage (3468 mL at 3.0 V) and temperature (3202 mL at 60 ◦C) over a 300 min electrolysis time. However optimal operating conditions are determined to be 1 M KOH 2.5 V and 25 ◦C balancing performance and energy efficiency. The improved performance is primarily attributed to enhanced ionic conductivity reduced internal resistance and the synergistic catalytic activity of the Cu-integrated NiZnFeOx coating.

The increasing global demand for clean energy highlights hydrogen as a strategic energy carrier due to its high energy density and carbon-free utilization. Currently steam methane reforming (SMR) is the most widely applied method for hydrogen production; however its high CO2 emissions undermine the environmental benefits of hydrogen. Blue hydrogen production integrates carbon capture and storage (CCS) technologies to overcome this drawback in the SMR process significantly reducing greenhouse gas emissions. This study integrated a MATLAB-R2025b-based plug flow reactor (PFR) model for SMR kinetics with an Aspen HYSYS-based CCS system. The effects of reformer temperature (600–1000 ◦C) and steam-to-carbon (S/C) ratio (1–5) on hydrogen yield and CO2 emission intensity were investigated. Results show that hydrogen production increases with temperature reaching maximum conversion at 850–1000 ◦C while the optimum performance is achieved at S/C ratios of 2.5–3.0 balancing high hydrogen yield and minimized methane slip. Conventional SMR generates 9–12 kgCO2/kgH2 emissions whereas SMR + CCS reduces this to 2–3 kgCO2/kgH2 achieving more than 75% reduction. The findings demonstrate that SMR + CCS integration effectively mitigates emissions and provides a sustainable bridging technology for blue hydrogen production supporting the transition toward lowcarbon energy systems.