United Kingdom

The research focuses on enhancing hydrogen production using a blend of municipal solid waste (MSW) with Biomass and mixed plastic waste (MPW) under the Bioenergy with Carbon Capture Utilisation and Storage (BECCUS) concept. The key challenges include optimising the feedstock blends and gasification process parameters to maximise hydrogen yield and carbon dioxide capture. This study introduces a novel approach that employs sorption-enhanced gasification and a high-temperature regenerator reactor. Using this method syngas streams with high hydrogen contents of up to 93 mol% and 66 mol% were produced respectively. Thermodynamic simulations with Aspen Plus® validated the integrated system for achieving high-purity hydrogen (99.99 mol%) and effective carbon dioxide isolation. The system produced 70.33 molH2 /kgfeed when using steam as a gasifying agent while 37.95 molH2 /kgfeed was produced under air gasification conditions. Case I employed a mixture of MSW and wood residue at a ratio of 1:1.25 with steam and calcium oxide added at 2:1 and 0.92:1 respectively resulting in 68.80 molH2 /kgfeed and a CO2 capture efficiency of 92 %. Case II utilised MSW and MPW at a 1:1 ratio with steam and calcium oxide at 2:1 and 0.4:1 respectively producing 100.17 molH2 /kgfeed and achieving a 90.09 % CO2 capture efficiency. The optimised parameters significantly improve hydrogen yield and carbon capture offering valuable insights for BECCUS applications.

Green hydrogen is likely to play a major role in decarbonising the aviation industry. It is crucial to understand the effects of microstructure on hydrogen redistribution which may be implicated in the embrittlement of candidate fuel system metals. We have developed a multiscale finite element modelling framework that integrates micromechanical and hydrogen transport models such that the dominant microstructural effects can be efficiently accounted for at millimetre length scales. Our results show that microstructure has a significant effect on hydrogen localisation in elastically anisotropic materials which exhibit an interesting interplay between microstructure and millimetre-scale hydrogen redistribution at various loading rates. Considering 316L stainless steel and nickel a direct comparison of model predictions against experimental hydrogen embrittlement data reveals that the reported sensitivity to loading rate may be strongly linked with rate-dependent grain scale diffusion. These findings highlight the need to incorporate microstructural characteristics in hydrogen embrittlement models.

With the transition to a fully renewable energy grid arises the need for a green source of stability and baseload support which classical renewable generation such as wind and solar cannot offer due to their uncertain and highly-variable generation. In this paper we study whether green hydrogen can close this gap as a source of supplemental generation and storage. We design a two-stage mixed-integer stochastic optimization model that accounts for uncertainties in renewable generation. Our model considers the investment in renewable plants and hydrogen storage as well as the operational decisions for running the hydrogen storage systems. For the data considered we observe that a fully renewable network driven by green hydrogen has a greater potential to succeed when wind generation is high. In fact the main investment priorities revealed by the model are in wind generation and in liquid hydrogen storage. This long-term storage is more valuable for taking full advantage of hydrogen than shorter-term intraday hydrogen gas storage. In addition we note that the main driver for the potential and profitability of green hydrogen lies in the electricity demand and prices as opposed to those for gas. Our model and the investment solutions proposed are robust with respect to changes in the investment costs. All in all our results show that there is potential for green hydrogen as a source of baseload support in the transition to a fully renewable-powered energy grid.

From an environmental standpoint carbon-free energy carriers such as ammonia and hydrogen are essential for future energy systems. However their hightemperature chemical behavior remains insufficiently understood posing challenges for the development and optimization of advanced combustion technologies. Ammonia in particular is globally available and cost-effective especially for energy-intensive industries. The addition of ammonia or hydrogen to methane significantly reduces the accuracy of existing predictive models. Therefore validated and detailed data are urgently needed to enable reliable design and performance predictions. This review highlights the compatibility of ammonia with existing combustion infrastructure facilitating a smoother transition to more sustainable heating methods without the need for entirely new systems. Applications in high-temperature heating processes such as metal processing ceramics and glass production and power generation are of particular interest. This review focuses on the systematic assessment of alternative fuel mixtures comprising ammonia and hydrogen as well as natural gas with particular consideration of existing safety-related parameters and combustion characteristics. Fundamental quantities such as the laminar burning velocity are discussed in the context of their relevance for fuel mixtures and their scalability toward turbulent flame propagation which is of critical importance for industrial burner and reactor design. The influence of fuel composition on ignition limits is examined as these are essential parameters for safety margin definitions and operational boundary conditions. Furthermore flame stability in mixed-fuel systems is addressed to evaluate the practical feasibility and robustness of combustion under varying process conditions. A detailed overview of current diagnostic and analysis methods follows encompassing both pollutant measurement techniques and the detection of key radical species. These diagnostics form the experimental basis for reaction kinetics modeling and mechanism validation. Given the importance of emission formation in combustion systems a dedicated subsection summarizes major emission trends even though a comprehensive treatment would exceed the scope of this review. Thermal radiation effects which are highly relevant for heat transfer and system efficiency in large-scale applications are then reviewed. In parallel current developments in numerical simulation approaches for industrial-scale combustion systems are presented including aspects of model accuracy boundary conditions and computational efficiency. The review also incorporates insights from materials engineering particularly regarding high-temperature material performance corrosion resistance and compatibility with combustion products. Based on these interdisciplinary findings operational strategies for high-temperature furnaces are outlined and selected industrial reference systems are briefly presented. This integrated approach aims to support the design optimization and safe operation of next-generation combustion technologies utilizing carbon-free or low-carbon fuels.

This study presents a techno-economic environmental risk analysis (TERA) of large-scale green hydrogen production using Alkaline Water Electrolysis (AWE) and Proton Exchange Membrane (PEM) systems. The analysis integrates commercial data market insights and academic forecasts to capture variability in capital expenditure (CAPEX) efficiency electricity cost and capacity factor. Using Libya as a case study 81 scenarios were modelled for each technology to assess financial and operational trade-offs. For AWE CAPEX is projected between $311 billion and $905.6 billion for 519 GW (gigawatts) of installed capacity equivalent to 600–1745 $/kW. PEM systems show a wider range of $612 billion to $1020 billion for 510 GW translating to 1200–2000 $/kW. Results indicate that AWE while requiring greater land use provides significant cost advantages due to lower capital intensity and scalability. In contrast PEM systems offer compact design and operational flexibility but at substantially higher costs. The five most economical scenarios for both technologies consistently feature low CAPEX and high efficiency while sensitivity analyses confirm these two parameters as the dominant cost drivers. The findings emphasise that technology choice should reflect context-specific priorities such as land availability budget and performance needs. This study provides actionable guidance for policymakers and investors developing cost-effective hydrogen infrastructure in emerging green energy markets.

Reducing CO2 emissions is an increasingly important goal in general aviation. The dual-fuel hydrogen–kerosene combustion process has proven to be a suitable technology for use in small aircraft. This robust and reliable technology significantly reduces CO2 emissions due to the carbon-free combustion of hydrogen during operation while pure kerosene or sustainable aviation fuel (SAF) can be used in safety-critical situations or in the event of fuel supply issues. Previous studies have demonstrated the potential of this technology in terms of emissions performance and efficiency while also highlighting challenges related to abnormal combustion phenomena such as knocking and pre-ignition which limit the maximum achievable hydrogen energy share. However the causes of such phenomena—especially regarding the role of lubricating oils—have not yet been sufficiently investigated in hydrogen engines making this a crucial area for further development. In this paper investigations at the TU Wien Institute of Powertrain and Automotive Technology concerning the role of different engine oils in influencing pre-ignition tendencies in a hydrogen–kerosene dual-fuel engine are described. A specialized test procedure was developed to account for the unique combustion characteristics of the dual-fuel process along with a detailed purge procedure to minimize oil carryover. Multiple engine oils with varying compositions were tested to evaluate their influence on pre-ignition tendencies with a particular focus on additives containing calcium magnesium and molybdenum known for their roles in detergent and anti-wear properties. Additionally the study addressed the contribution of particles to pre-ignition occurrences. The results indicate that calcium and magnesium exhibit no notable impact on pre-ignition behavior; however the addition of molybdenum results in a pronounced reduction in pre-ignition events which could enable a higher hydrogen energy share and thus decrease CO2 emissions in the context of hydrogen dual-fuel aviation applications.

Achieving transport decarbonization depends on electric vehicle (EV) and fuel cell vehicle (FCV) deployment yet their material demands and impacts vary by vehicle type. This study explores how powertrain preferences in light-duty vehicles (LDVs) and heavy-duty vehicles (HDVs) shape future resource use and material-related environmental outcomes. Using dynamic material flow analysis and prospective life cycle assessment we assess three scenarios. In the S3 EV-dominant scenario 2050 lithium and cobalt demand rises by up to 11.9-fold and 1.8-fold relative to 2020 with higher global warming and human toxicity impacts. The S2 FCV-dominant scenario leads to a 21.7-fold increase in platinum-group metal demand driving up freshwater ecotoxicity and particulate emissions. A balanced S1 scenario EVs in LDVs and FCVs in HDVs yields moderate material demand and environmental burdens. These findings demonstrate that no single pathway can fully resolve material-related impacts while combining EVs and FCVs across LDVs and HDVs enables a more balanced and sustainable transition.

This study presents a comprehensive review of the viability of hydrogen as an energy carrier for offshore wind energy compared to existing electricity carrier systems. To enable a state-of-the-art system comparison a review of wind-to-hydrogen energy conversion and transmission systems is conducted alongside wind-to-electricity systems. The review reveals that the wind-to-hydrogen energy conversion and transmission system becomes more cost-effective than the wind-to-electricity conversion and transmission system for offshore wind farms located far from the shore. Electrical transmission systems face increasing technical and economic challenges relative to the hydrogen transmission system when the systems move farther offshore. This study also explores the feasibility of using seawater for hydrogen production to conserve freshwater resources. It was found that while this approach conserves freshwater and can reduce transportation costs it increases overall system costs due to challenges such as membrane fouling in desalination units. Findings indicated that for this approach to be sustainable proper management of these challenges and responsible handling of saline waste are essential. For hydrogen energy transmission this paper further explores the potential of repurposing existing oil and gas pipeline infrastructure instead of constructing new pipelines. Findings indicated that with proper retrofitting the existing natural gas pipelines could provide a cost-effective and environmentally sustainable solution for hydrogen transport in the near future.

As global efforts to decarbonize intensify hydrogen produced via renewable electricity has emerged as a pivotal energy vector for a sustainable industrial future. This commentary provides a critical analysis of the current state of the hydrogen economy in Europe detailing the core principles operational mechanisms and industrial status of four primary water electrolysis technologies: alkaline (ALK) proton exchange membrane (PEM) solid oxide (SOEC) and anion exchange membrane (AEM). Furthermore it explores the significant socio-political challenges inherent in producing green hydrogen in non-EU nations for subsequent import into the European market.

Hydrogen (H2) is a promising energy carrier for decarbonization; however efficient storage remains a key challenge. Porous materials offer potential for enhanced H2 densification and may enable the development of next-generation lightweight storage systems. A major limitation of such materials is their fine powder form which hampers retention and processability. In this study composite membranes comprising a polymer of intrinsic microporosity (PIM-1) matrix and a polytriphenylamine (PTPA)-based conjugated microporous polymer (CMP) filler were developed. The composites are mechanically robust forming self-standing membranes that retain stability under high temperatures and humidity. H2 storage capacities of the membranes showed excess gravimetric uptakes of 1.03 wt% at 1 bar and 1.84 wt% at 50 bar (77 K) with total capacities reaching 3.22 wt% at 100 bar. These values are significantly higher than those of pristine PIM-1 which achieved 0.87 wt% 1.64 wt % and 2.89 wt% under the same conditions. Net adsorption isotherms demonstrate the potential of the composites to outperform conventional compression storage up to 10 bar at 77 K. Additionally the composites exhibit high mass transfer coefficients (3.42 min− 1 ) indicating strong H2 affinity and faster charging rates compared with the pristine PIM-1 membrane (2.79 min− 1 ).