Production & Supply Chain

In recent years the intensification of human activities has led to an increase in waste production and energy demand. The treatment of pollutants contained in wastewater coupled to energy recovery is an attractive solution to simultaneously reduce environmental pollution and provide alternative energy sources. Hydrogen represents a clean energy carrier for the transition to a decarbonized society. Hydrogen can be generated by photosynthetic water splitting where oxygen and hydrogen are produced and the process is driven by the light energy absorbed by the photocatalyst. Alternatively hydrogen may be generated from hydrogenated pollutants in water through photocatalysis and the overall reaction is thermodynamically more favourable than water splitting for hydrogen. This review is focused on recent developments in research surrounding photocatalytic and photoelectrochemical hydrogen production from pollutants that may be found in wastewater. The fundamentals of photocatalysis and photoelectrochemical cells are discussed along with materials and efficiency determination. Then the review focuses on hydrogen production linked to the oxidation of compounds found in wastewater. Some research has investigated hydrogen production from wastewater mixtures such as olive mill wastewater juice production wastewater and waste activated sludge. This is an exciting area for research in photocatalysis and semiconductor photoelectrochemistry with real potential for scale up in niche applications.

Low-cost alkaline water electrolysis from renewable energy sources (RESs) is suitable for large-scale hydrogen production. However fluctuating RESs lead to poor performance of alkaline water electrolyzers (AWEs) at low loads. Here we explore two urgent performance issues: inefficiency and inconsistency. Through detailed operation process analysis of AWEs and the established equivalent electrical model we reveal the mechanisms of inefficiency and inconsistency of low-load AWEs are related to the physical structure and electrical characteristics. Furthermore we propose a multi-mode self-optimization electrolysis converting strategy to improve the efficiency and consistency of AWEs. In particular compared to a conventional dc power supply we demonstrate using a lab-scale and large-scale commercially available AWE that the maximum efficiency can be doubled while the operation range of the electrolyzer can be extended from 30–100% to 10–100% of rated load. Our method can be easily generalized and can facilitate hydrogen production from RESs.

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.

The use of hydrogen as an energy carrier represents a promising alternative for mitigating climate change. However its practical application requires achieving a high degree of purity throughout the production process. In this study the influence of the type of catalytic support on H2 production via steam glycerol reforming was evaluated with the objective of obtaining syngas with the highest possible H2 concentration. Three types of support were analyzed: two natural materials (zeolite and dolomite) and one metal oxide alumina. Alumina and dolomite were coated with Ni at different loadings while zeolite was only evaluated without Ni. Reforming experiments were carried out at a constant temperature of 850 ◦C with continuous monitoring of H2 CO2 CO and CH4 concentrations. The results showed that zeolite yielded the lowest H2 concentration (51%) mainly due to amorphization at high temperatures and the limited effectiveness of physical adsorption processes. In contrast alumina and dolomite achieved H2 purities of around 70% which increased with Ni loading. The improvement was particularly significant in dolomite owing to its higher porosity and the recarbonation processes of CaO enabling H2 purities of up to 90%.

Natural hydrogen or "white hydrogen" has recently garnered attention as a viable and cost-effective energy resource due to its low-carbon footprint and high energy density positioning it as a key contributor to the transition towards a sustainable low-carbon energy system. This study represents Alberta’s first systematic effort to evaluate natural hydrogen potential in the province using publicly available geological geospatial and gas composition datasets. By mapping hydrogen occurrences against key geological features in the Western Canadian Sedimentary Basin (WCSB) we identify regions with strong geological potential for natural hydrogen generation migration and accumulation while addressing data uncertainties. Within the WCSB formations like the Montney Cardium Bearpaw Manville Belly River McMurray and Lea Park are identified as zones likely for hydrogen generation by prominent mechanisms including hydrocarbon decomposition water-rock reactions with iron-rich sediments and organic pyrolysis. Formation proximity to the underlying Canadian Shield may also suggest potential for basement-derived hydrogen migration via deep-seated faults and shear zones. Salt deposits (Elk Point Group - Prairie evaporites Cold Lake and Lotsberg) and deep shales (e.g. Kaskapau Lea Park Wapiabi) provide effective cap rock potential while reservoirs like porous sandstone (e.g. Dunvegan Spirit River Cardium) and fractured carbonate (e.g. Keg River) formations offer favorable accumulation conditions. Hydrogen occurrences in relation to geological features identify Southern Eastern and West-Central plains as prominent natural Hydrogen generation and accumulation areas. Alberta’s established energy infrastructure as well as subsurface expertise positions it as a potential leader in natural hydrogen exploration. As Alberta’s first systematic investigation this study provides a preliminary assessment of natural hydrogen potential and outlines recommended next steps to guide future exploration and research. Targeted research on specific generation and accumulation mechanisms and source identification through isotopic and geochemical fingerprinting will be crucial for exploration de-risking and viability assessment in support of net-zero emission initiatives.

This study explores the generation of natural hydrogen through the serpentinization of onshore ultramafic rocks highlighting its potential as a clean energy resource. By investigating critical factors such as mineral composition temperature and pressure the research develops an empirical model using multiple regression analysis to predict hydrogen generation rates under varying geological conditions. A novel five-stage volumetric calculation methodology is introduced to estimate hydrogen production from ultramafic rock bodies. The application of this framework to the Giles Complex an ultramafic-mafic intrusion in Australia suggests a hydrogen generation potential of approximately 2.24 × 1013 kg of hydrogen through partial serpentinization. This estimate is based on the assumed mineral composition depth and temperature conditions within the intrusion which influence the extent of serpentinization reactions. The findings demonstrate the significant potential of ultramafic complexes for natural hydrogen production and provide a foundation for advancing natural hydrogen exploration refining predictive models and supporting sustainable energy development.

This study evaluates the feasibility of employing rainwater as an alternative feedstock for hydrogen production via electrolysis. While conventional systems typically rely on high-purity water—such as deionized or distilled variants—these can be cost-prohibitive and environmentally intensive. Rainwater being naturally available and minimally treated presents a potential sustainable alternative. In this work a series of comparative experiments was conducted using a proton exchange membrane electrolyzer system operating with both deionized water and rainwater collected from different Austrian locations. The chemical composition of rainwater samples was assessed through inductively coupled plasma ion chromatography and visual rapid tests to identify impurities and ionic profiles. The electrolyzer’s performance was evaluated under equivalent operating conditions. Results indicate that rainwater in some cases yielded comparable or marginally superior efficiency compared to deionized water attributed to its inherent ionic content. The study also examines the operational risks linked to trace contaminants and explores possible strategies for their mitigation.