Production & Supply Chain

By offering promising solutions to two critical issues – the integration of renewable energies into energy systems and the decarbonization of existing hydrogen applications – green hydrogen production through water electrolysis is set to play a crucial role in addressing the major challenges of the energy transition. However the successful integration of renewable energy sources relies on gaining accurate insights into the impacts that intermittent electrical supply conditions induce on electrolyzers. Despite the rising importance of addressing intermittency issues to accelerate the widespread adoption of renewable energy sources the state-of-the-art lacks research providing an in-depth understanding of these concerns. This paper endeavors to offer a comprehensive review of existing research focusing on proton exchange membrane (PEM) and alkaline electrolysis technologies operating under intermittent operation. Despite growing interest over the last ten years the review underscores the scarcity of industrial-scale databases for quantifying these impacts.

The escalating global pursuit of environmentally benign energy alternatives has spurred intensive investigations into sustainable hydrogen generation technologies. Although hydrogen energy can be produced via multiple approaches the integration of nanotechnology materials in its generation results in its production improvements and efficiency of the production methods. Nanotechnology with its astonishing ability to control materials at the atomic and molecular scale has emerged as a vital technology for improving the efficiency and affordability of hydrogen production from renewable energy sources. This technology provides a unique platform for creating materials with specific properties for energy conversion and storage. Nanotechnology is accelerating the transition to a hydrogen economy by boosting hydrogen production efficiency and storage. Its applications span from enhancing water-splitting catalysts to developing advanced membranes and photocatalysts. These nanomaterial-based innovations are crucial for producing clean hydrogen and its effective storage. Nevertheless nanotechnology highlights the significant role of nanomaterials in overcoming the kinetic challenges associated with hydrogen evolution reactions which can be attained through several features like increased surface area enhanced catalytic activity and improved charge transfer. Therefore this study explores the latest advancements in nanomaterials and their catalytic impact on hydrogen generation particularly in photocatalysis electrocatalysis and photoelectrochemical systems. The study has examined the nanomaterials’ production characterization and performance their integration into renewable energy systems and their potential for widespread commercial use.

The U.S. produces 10 million metric tons (MMT) of hydrogen annually emitting about 41 MMT of carbon dioxide equivalents (CO2-eqs). With rising hydrogen demand and new emission regulations integrating conventional and novel hydrogen production systems is crucial. This study presents an integrated optimization framework to model diversified hydrogen economies as mixed integer linear programs (MILPs). Moreover the accounting of emissions extends to the system exterior (scope 3) thus providing a comprehensive sustainability assessment. The primary focus of the presented computational example is to analyze the impact of scope 3 emissions particularly material emissions during the construction phase on process system optimization while complying with stringent environmental constraints such as carbon limits. By evaluating emission reduction scenarios the model highlights the role of power purchase agreements (PPAs) from renewable sources and the trade-offs between conventional and novel hydrogen production technologies. The key findings indicate that while electrolyzer-based systems (PEM and AWE) offer potential for emission reduction their high energy demand and significant scope 3 material emissions pose challenges for a complete transition in the near term. The study identified two optimal design configurations: one utilizing PPAs as the primary energy source coupled with the conventional SMR-CCS process and another that combines both conventional (SMR-CCS) and novel hydrogen production technologies under a hybrid purview. Ultimately the findings contribute toward the ongoing efforts to achieve true net-carbon neutrality.

The urgency for sustainable and efficient hydrogen production has increased interest in heterostructured nanomaterials known for their excellent photocatalytic properties. Traditional synthesis methods often rely on trial-and-error resulting in inefficiencies in material discovery and optimization. This work presents a new AI-driven framework that overcomes these challenges by integrating advanced machine-learning techniques specific to heterostructured nanomaterials. Graph Neural Networks (GNNs) enable accurate representations of atomic structures predicting material properties like bandgap energy and photocatalytic efficiency within ±0.05 eV. Reinforcement Learning optimises synthesis parameters reducing experimental iterations by 40% and boosting hydrogen yield by 15–20%. Physics-Informed Neural Networks (PINNs) successfully predict reaction pathways and intermediate states minimizing synthesis errors by 25%. Variational Autoencoders (VAEs) generate novel material configurations improving photocatalytic efficiency by up to 15%. Additionally Bayesian Optimisation enhances predictive accuracy by 30% through efficient hyperparameter tuning. This holistic framework integrates material design synthesis optimization and experimental validation fostering a synergistic data flow. Ultimately it accelerates the discovery of novel heterostructured nanomaterials enhancing efficiency scalability and yield thus moving closer to sustainable hydrogen production with improvements in photolytic efficiency setting a benchmark for AI-assisted research.

On the path to an emission free energy economy proton exchange membrane water electrolysis (PEMWE) is a promising technology for a sustainable production of green hydrogen at high current densities and thus high production rates. Long lifetime increasing the current density and the reduction of platinum group metal loadings are major challenges for a widespread implementation of PEMWE. In this context this work investigates the aging of a PEMWE stack operating at 4 A cm-2 which is twice the nominal current density of commercial electrolyzers. Specifically an 8-cells PEMWE stack using catalyst coated membranes (CCMs) with different platinum group metal (PGM) loading was operated for 2200 h. To understand degradation phenomena physical ex-situ analyses such as scanning electron microscopy (SEM) atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were carried out. The same aging mechanism were observed in all cells independent on their position in stack or the specific PGM loading of the membrane electrode assembly (CCM): (i) a decrease of ohmic resistance over time related to membrane thinning (ii) a significant loss of ionomer at anodes (iii) loss of noble metal from the electrodes leading to deposition of small Ir and Pt concentrations in the membrane (iv) heterogeneous enrichment of Ti on the cathode side likely originating from the cathode-side of the Ti bipolar plates (BPPs). These results are in good agreement with the electrochemical performance loss. Thus we were able to identify the degradation phenomena that dominate under high-current operation and their impact on performance.

Sorption-enhanced steam reforming (SorESR) is an advanced thermochemical process integrating in-situ CO2 capture via solid sorbents to significantly enhance hydrogen production and purity. By coupling CO2 adsorption with steam reforming SorESR shifts the reaction equilibrium toward increased H₂ yield surpassing the limitations of conventional steam reforming (SR). The efficacy of SorESR critically depends on the physicochemical properties of the solid CO2 sorbents employed. This review critically evaluates widely studied sorbents including Ca-based Mg-based hydrotalcite-like and alkali ceramic sorbents focusing on their CO2 capture capacity reaction kinetics thermal stability and cyclic durability under SR conditions. Furthermore recent progress in multifunctional sorbent-catalysts that synergistically facilitate catalytic steam reforming alongside CO2 sorption is critically discussed. Moreover the review summarises recent performance achievements and proposes strategies to improve sorbent capacity and reaction kinetics thereby making the SorESR process more appealing for commercial applications. Large-scale SorESR implementation is expected to substantially increase hydrogen production efficiency while concurrently reducing CO2 emissions and advancing sustainable energy technologies. This review offers novel insights into the development of advanced sorbent-catalyst systems and provides new strategies for enhancing SorESR efficiency and scalability for commercial H2 Production.

In the context of mounting concerns over carbon emissions and the need to accelerate the energy transition green hydrogen has emerged as a strategic solution for decarbonizing hard-to-abate sectors. This paper introduces a methodological innovation by proposing the Green Hydrogen Efficiency Index (GHEI) a unified and quantitative framework that integrates multiple stages of the hydrogen value chain into a single comparative metric. The index encompasses six core criteria: electricity source water treatment electrolysis efficiency compression end-use conversion and associated greenhouse gas emissions. Each are normalized and weighted to reflect different performance priorities. Two weighting profiles are adopted: a first profile which assigns equal importance to all criteria referred to as the balanced profile and a second profile derived using the analytic hierarchy process (AHP) based on structured expert judgment named the AHP profile. The methodology was developed through a systematic literature review and was applied to four representative case studies sourced from the academic literature covering diverse configurations and geographies. The results demonstrate the GHEI’s capacity to distinguish the energy performance of different green hydrogen routes and support strategic decisions related to technology selection site planning and logistics optimization. The results highlight the potential of the index to contribute to more sustainable hydrogen value chains and advance decarbonization goals by identifying pathways that minimize energy losses and maximize system efficiency

The increasing interest in off-grid green hydrogen production has elevated the importance of reliable techno-economic assessment (TEA) tools to support investment and planning decisions. However limited operational data and inconsistent modeling approaches across existing tools introduce significant uncertainty in cost estimations. This study presents a comprehensive review and comparative analysis of seven TEA tools—ranging from simplified calculators to advanced hourly based simulation platforms—used to estimate the Levelized Cost of Hydrogen (LCOH) in off-grid Hydrogen Production Plants (HPPs). A standardized simulation framework was developed to input consistent technical economic and financial parameters across all tools allowing for a horizontal comparison. Results revealed a substantial spread in LCOH values from EUR 5.86/kg to EUR 8.71/kg representing a 49% variation. This discrepancy is attributed to differences in modeling depth treatment of critical parameters (e.g. electrolyzer efficiency capacity factor storage and inflation) and the tools’ temporal resolution. Tools that included higher input granularity hourly data and broader system components tended to produce more conservative (higher) LCOH values highlighting the cost impact of increased modeling realism. Additionally the total project cost—more than hydrogen output—was identified as the key driver of LCOH variability across tools. This study provides the first multi-tool horizontal testing protocol a methodological benchmark for evaluating TEA tools and underscores the need for harmonized input structures and transparent modeling assumptions. These findings support the development of more consistent and reliable economic evaluations for off-grid green hydrogen projects especially as the sector moves toward commercial scale-up and policy integration.

This study evaluated the economic feasibility of producing hydrogen from natural gas via thermal degradation in a plasma reactor. Plasma pyrolysis where natural gas passes through the space between electrodes and serves as the working medium enables high hydrogen yields without emitting carbon monoxide or carbon dioxide. Instead the primary products are hydrogen and solid carbon. Unlike conventional methods this approach requires no catalysts addressing a major technological limitation. A thermodynamic equilibrium model based on Gibbs free energy minimization was used to analyze the process over a temperature range of 500–2500 K. The results indicate an optimal temperature of approximately 1500 K which achieved a 99.5% methane conversion by mass. Considering the capital and operating costs and profit margins the hydrogen production cost was estimated at 3.49 EUR/kg. The sensitivity analysis revealed that the price of solid carbon had the most significant impact which potentially raised the hydrogen cost to 4.53 EUR/kg or reduced it to 1.70 EUR/kg.

With the intensification of the global energy crisis hydrogen has attracted significant attention as a high-energy-density and zero-emission clean energy source. Traditional hydrogen production methods are dependent on fossil fuels and simultaneously contribute to environmental pollution. The aqueous phase reforming (APR) of renewable biomass and its derivatives has emerged as a research hotspot in recent years due to its ability to produce green hydrogen in an environmentally friendly manner. This review provides an overview of the advancements in APR of lignocellulosic biomass as a sustainable and environmentally friendly method for hydrogen production. It focuses on the reaction pathways of various biomass feedstocks (such as glucose cellulose and lignin) as well as the types and performance of catalysts used in the APR process. Finally the current challenges and future prospects in this field are briefly discussed.