Production & Supply Chain

High-temperature electrolysis offers a solution for industry decarbonisation by high-efficiency hydrogen production. This study presents a system based on Solid Oxide Electrolysis Cells (SOEC) fed by photovoltaic and waste heat recovery for hydrogen blending with natural gas in industrial burners. The aim of this work is to assess techno-economic feasibility of the proposed configuration investigating hydrogen blending limits Levelized Cost of Hydrogen (LCOH) and decarbonisation cost. LCOH values below 6 €/kgH2 cannot be achieved at current SOEC costs. The system can be applied without significant burner modifications since maximum hydrogen volumetric fractions are less than 20 %. Higher efficiency and emission reduction potential in comparison to alkaline electrolysers can be achieved but they are offset by higher LCOH and carbon abatement costs. Forthcoming reduction in SOEC costs can improve the cost-effectiveness and high natural gas prices experienced during the energy crisis make the decarbonisation cost competitive with the emission trading system.

N-type sulfide semiconductors are promising photocatalysts due to their broad visible-light absorption facile synthesis and chemical diversity. However photocorrosion and limited electron transport in one-step excitation and solid-state Z-scheme systems hinder efficient overall water splitting. Liquidphase Z-schemes offer a viable alternative but sluggish mediator kinetics and interfacial side reactions impede their construction. Here we report a stable Z-scheme system integrating n-type CdS and BiVO₄ with a [Fe(CN)₆]³⁻/[Fe(CN)₆]⁴⁻ mediator achieving 10.2% apparent quantum yield at 450 nm with stoichiometric H₂/O₂ evolution. High activity reflects synergies between Pt@CrOx and Co3O4 cocatalysts on CdS and cobalt-directed facet asymmetry in BiVO₄ resulting in matched kinetics for hydrogen and oxygen evolution in a reversible mediator solution. Stability is dramatically improved through coating CdS and BiVO4 with different oxides to inhibit Fe4[Fe(CN)6]3 precipitation and deactivation by a hitherto unrecognized mechanism. Separate hydrogen and oxygen production is also demonstrated in a twocompartment reactor under visible light and ambient conditions. This work unlocks the long-sought potential of n-type sulfides for efficient durable and safe solar-driven hydrogen production.

Hydrogen plays a key role in many industrial applications and is currently seen as one of the most promising energy vectors. Many efforts are being made to produce hydrogen with zero CO 2 footprint via water electrolysis powered by renewable energies. Nevertheless the use of fossil fuels is essentialin the short term. The conventional coal gasification and steam methane reforming processes for hydrogen production are undesirable due to the huge CO2 emissions. A cleaner technologybased on natural gas that has received special attention in recent years is methane pyrolysis. The thermal decomposition of methane gives rise to hydrogen and solid carbon and thus the release of greenhouse gases is prevented. Therefore methane pyrolysis is a CO2-free technology that can serve as a bridge from fossil fuels torenewable energies.

As global energy demand increases and reliance on fossil fuels becomes unsustainable hydrogen presents a promising clean energy alternative due to its high energy density and potential for significant CO2 emission reductions. However current hydrogen production methods largely depend on fossil fuels contributing to considerable CO2 emissions and underscoring the need to transition to renewable energy sources and improved production technologies. Life Cycle Analysis (LCA) is essential for evaluating and optimizing hydrogen production by assessing environmental impacts such as Global Warming Potential (GWP) energy consumption toxicity and water usage. The key findings indicate that energy sources and feedstocks heavily influence the environmental impacts of hydrogen production. Hydrogen production from renewable energy sources particularly wind solar and hydropower demonstrates significantly lower environmental impacts than grid electricity and fossil fuel-based methods. Conversely hydrogen production from grid electricity primarily derived from fossil fuels shows a high GWP. Furthermore challenges related to data accuracy economic analysis integration and measuring mixed gases are discussed. Future research should focus on improving data accuracy assessing the impact of technological advancements and exploring new hydrogen production methods. Harmonizing assessment methodologies across different production pathways and standardizing functional units such as “1 kg of hydrogen produced “ are critical for enabling transparent and consistent sustainability evaluations. Techniques such as stochastic modelling and Monte Carlo simulations can improve uncertainty management and enhance the reliability of LCA results.

Hydrogen gas is a promising clean-energy vector that can alleviate the current imbalance between energy supply and demand diversify the energy portfolio and underpin the sustainable development of oil and gas resources. This study pinpoints the factors that govern hydrogen quantification by pulsed-neutron logging. Monte Carlo simulations were performed to map the spatial distribution of capture γ-rays in formations saturated with either water or hydrogen and to systematically assess the effects of pore-fluid composition hydrogen density gas saturation lithology and borehole-fluid type. The results show that the counts of capture γ-rays are litter in hydrogen-bearing formations. For lowto moderate-porosity rocks the dynamic response window for hydrogensaturated pores is approximately 10% wider than that for methane-saturated pores. Increasing hydrogen density or decreasing gas saturation raises the capture-γ ratio while narrowing the dynamic range. Changes in borehole fluid substantially affect the capture-γ ratio yet have only a minor impact on the dynamic range. Lithology imposes an additional control: serpentinite enriched in structural water generates markedly higher capture-γ ratios that may complicate the quantitative evaluation of hydrogen.

Hydrogen has the potential to revolutionize how we power our lives from transportation to energy production. This study aims to compare the climate change impacts and the main factors affecting them for different categories of hydrogen production including grey hydrogen (SMR) blue hydrogen (SMR-CCS) turquoise hydrogen (TDM) and green hydrogen (PEM electrolysis). Grey hydrogen blue hydrogen and turquoise hydrogen which are derived from fossil sources are produced using natural gas and green hydrogen is produced from water and renewable electricity sources. When considering natural gas as a feedstock it is sourced from the pipeline route connected to Russia and through the liquefied natural gas (LNG) route from the USA. The life cycle assessment (LCA) result showed that grey hydrogen had the highest emissions with the LNG route showing higher emissions 13.9 kg CO2 eq. per kg H2 compared to the pipeline route 12.3 kg CO2 eq. per kg H2. Blue hydrogen had lower emissions due to the implementation of carbon capture technology (7.6 kg CO2 eq. per kg H2 for the pipeline route and 9.3 kg CO2 eq. per kg H2 for the LNG route) while turquoise hydrogen had the lowest emissions (6.1 kg CO2 eq. per kg H2 for the pipeline route and 8.3 kg CO2 eq. per kg H2 for the LNG route). The climate change impact showed a 12–25% increase for GWP20 compared to GWP100 for grey blue and turquoise hydrogen. The production of green hydrogen using wind energy resulted in the lowest emissions (0.6 kg CO2 eq. per kg H2) while solar energy resulted in higher emissions (2.5 kg CO2 eq. per kg H2). This article emphasizes the need to consider upstream emissions associated with natural gas and LNG extraction compression liquefaction transmission and regasification in assessing the sustainability of blue and turquoise hydrogen compared to green hydrogen.

A key factor in reducing the cost of green hydrogen production projects using water electrolysis systems is to minimize the degradation of the electrolyzer stacks as this impacts the lifetime of the stacks and therefore the frequency of their replacement. To create a better understanding of the economics of stack degradation we present a linear optimization approach minimizing the costs of a green hydrogen supply chain including an electrolyzer with degradation modeling. By calculating the levelized cost of hydrogen depending on a variable degradation threshold the cost optimal time for stack replacement can be identified. We further study how this optimal time of replacement is affected by sensitivities such as the degradation scale the load-dependency of both degradation and energy demand and the costs of the electrolyzer. The variation of the identified major sensitivity degradation scale results in a difference of up to 9 years regarding the cost optimal time for stack replacement respectively lifetime of the stacks. Therefore a better understanding of the degradation impact is imperative for project cost reductions which in turn would support a proceeding hydrogen market ramp-up.

This prospective life cycle assessment (LCA) compares the environmental impacts of alkaline electrolyser (AE) and proton exchange membrane (PEM) electrolyser systems for green hydrogen production with a special focus on the stack components. The study evaluates both baseline and near-future advanced designs considering cradle-to-gate life cycle from material production to operation. The electricity source followed by the stacks are identified as major contributors to environmental impacts. No clear winner emerges between AE and PEM in relation to environmental impacts. The advanced designs show a reduced impact in most categories compared to baseline designs which can mainly be attributed to the increased current density. Advanced green hydrogen production technologies outperform grey and blue hydrogen production technologies in all impact categories except for minerals and metals resource use due to rare earth metals in the stacks. Next to increasing current density decreasing minimal load requirements. improving sustainable mining practices (including waste treatment) and low carbon intensity steel production routes can enhance the environmental performance of electrolyser systems aiding the transition to sustainable hydrogen production.

The transition toward low-carbon energy systems requires reliable tools for assessing renewable-based hydrogen production under real-world climatic and economic conditions. This study presents a novel probabilistic framework integrating the following three complementary elements: (1) a Photovoltaic Geographical Information System (PVGIS) for high-resolution location-specific solar energy data; (2) Metalog probability distributions for advanced modeling of variability and uncertainty in photovoltaic (PV) energy generation; and (3) Levelized Cost of Hydrogen (LCOH) calculations to evaluate the economic viability of hydrogen production systems. The methodology is applied to three diverse European locations—Lublin (Poland) Budapest (Hungary) and Malaga (Spain)—to demonstrate regional differences in hydrogen production potential. The results indicate annual PV energy yields of 108.3 MWh 124.6 MWh and 170.95 MWh respectively which translate into LCOH values of EUR 9.67/kg (Poland) EUR 8.40/kg (Hungary) and EUR 6.13/kg (Spain). The probabilistic analysis reveals seasonal production risks and quantifies the probability of achieving specific monthly energy thresholds providing critical insights for designing systems with continuous hydrogen output. This combined use of a PVGIS Metalog and LCOH calculations offers a unique decision-support tool for investors policymakers and SMEs planning green hydrogen projects. The proposed methodology is scalable and adaptable to other renewable energy systems enabling informed investment decisions and improved regional energy transition strategies.

Methanol steam reforming (MSR) represents a highly promising pathway for sustainable hydrogen production due to its favorable hydrogen-to-carbon ratio and relatively low operating temperatures. The performance of the MSR process is strongly dependent on the selection and rational design of catalysts which govern methanol conversion hydrogen selectivity and the suppression of undesired side reactions such as carbon monoxide formation. Moreover advancements in reactor configuration and thermal management strategies play a vital role in minimizing heat loss and enhancing heat and mass transfer efficiency. Effective carbon monoxide removal technologies are indispensable for obtaining high-purity hydrogen particularly for applications sensitive to CO contamination. This review systematically summarizes recent progress in catalyst development reactor design and gas purification technologies for MSR. In addition the key technical challenges and potential future directions of the MSR process are critically discussed. The insights provided herein are expected to contribute to the development of more efficient stable and scalable MSR-based hydrogen production systems.