Publications

To enable climate-neutral aviation improving the energy efficiency of aircraft is essential. The research project Synergies of Highly Integrated Transport Aircraft investigates cross-disciplinary synergies in aircraft and propulsion technologies to achieve energy savings. This study examines a fuel cell electric powered configuration with distributed electric propulsion. For this a reverse-engineered ATR 72-500 serves as a reference model for calibrating the methods and ensuring accurate performance modeling. A baseline configuration featuring a state-of-the-art turboprop engine with the same entry-into-service is also introduced for a meaningful performance comparison. The analysis uses an enhanced version of the Stanford University Aerospace Vehicle Environment (SUAVE) a Python-based aircraft design environment that allows for novel energy network architectures. This paper details the preliminary aircraft design process including calibration presents the resulting aircraft configurations and examines the integration of a fuel cell-electric energy network. The results provide a foundation for higher fidelity studies and performance comparisons offering insights into the trade-offs associated with hydrogen-based propulsion systems. All fundamental equations and methodologies are explicitly presented ensuring transparency clarity and reproducibility. This comprehensive disclosure allows the broader scientific community to utilize and refine these findings facilitating further progress in hydrogen-powered aviation technologies.

Electricity access deficits remain acute in Sub-Saharan Africa (SSA) where more than 600 million people lack reliable supply. Green hydrogen produced through renewablepowered electrolysis is increasingly recognized as a transformative energy carrier for decentralized systems due to its capacity for long-duration storage sector coupling and near-zero carbon emissions. This review adheres strictly to the PRISMA 2020 methodology examining 190 records and synthesizing 80 peer-reviewed articles and industry reports released from 2010 to 2025. The review covers hydrogen production processes hybrid renewable integration techno-economic analysis environmental compromises global feasibility and enabling policy incentives. The findings show that Alkaline (AEL) and PEM electrolyzers are immediately suitable for off-grid scenarios whereas Solid Oxide (SOEC) and Anion Exchange Membrane (AEM) electrolyzers present high potential for future deployment. For Sub-Saharan Africa (SSA) the levelized costs of hydrogen (LCOH) are in the range of EUR5.0–7.7/kg. Nonetheless estimates from the learning curve indicate that these costs could fall to between EUR1.0 and EUR1.5 per kg by 2050 assuming there is (i) continued public support for the technology innovation (ii) appropriate flexible and predictable regulation (iii) increased demand for hydrogen and (iv) a stable and long-term policy framework. Environmental life-cycle assessments indicate that emissions are nearly zero but they also highlight serious concerns regarding freshwater usage land occupation and dependence on platinum group metals. Namibia South Africa and Kenya exhibit considerable promise in the early stages of development while Niger demonstrates the feasibility of deploying modular community-scale systems in challenging conditions. The study concludes that green hydrogen cannot be treated as an integrated solution but needs to be regarded as part of blended off-grid systems. To improve its role targeted material innovation blended finance and policies bridging export-oriented applications to community-scale access must be established. It will then be feasible to ensure that hydrogen

Amid escalating global climate crises and the urgent imperative to meet the Paris Agreement’s carbon neutrality targets the steel industry—a leading contributor to global greenhouse gas emissions—confronts unprecedented challenges in driving sustainable industrial transformation through innovative low-carbon steelmaking technologies. This paper examines decarbonization technologies across three stages (source process and end-of-pipe) for two dominant steel production routes: the long process (BF-BOF) and the short process (EAF). For the BF-BOF route carbon reduction at the source stage is achieved through high-proportion pellet charging in the blast furnace and high scrap ratio utilization; at the process stage carbon control is optimized via bottom-blowing O2-CO2-CaO composite injection in the converter; and at the end-of-pipe stage CO2 recycling and carbon capture are employed to achieve deep decarbonization. In contrast the EAF route establishes a low-carbon production system by relying on green and efficient electric arc furnaces and hydrogen-based shaft furnaces. At the source stage energy consumption is reduced through the use of green electricity and advanced equipment; during the process stage precision smelting is realized through intelligent control systems; and at the end-of-pipe stage a closed-loop is achieved by combining cascade waste heat recovery and steel slag resource utilization. Across both process routes hydrogen-based direct reduction and green power-driven EAF technology demonstrate significant emission reduction potential providing key technical support for the low-carbon transformation of the steel industry. Comparative analysis of industrial applications reveals varying emission reduction efficiencies economic viability and implementation challenges across different technical pathways. The study concludes that deep decarbonization of the steel industry requires coordinated policy incentives technological innovation and industrial chain collaboration. Accelerating large-scale adoption of low-carbon metallurgical technologies through these synergistic efforts will drive the global steel sector toward sustainable development goals. This study provides a systematic evaluation of current low-carbon steelmaking technologies and outlines practical implementation strategies contributing to the industry’s decarbonization efforts.

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.

Underground Hydrogen Storage (UHS) is a promising solution to maximize the use of hydrogen as an energy carrier. This study presents a standardized methodology for assessing UHS quality by introducing the Underground Hydrogen Storage Suitability Index (UHSSI) which integrates three sub-indices: the Caprock Potential Index (CPI) the Reservoir Quality Index (RQI) and the Site Potential Index (SPI). Parameters such as porosity permeability lithology caprock thickness depth temperature and salinity are evaluated and ranked from 0 (unsuitable) to 5 (excellent). The methodology was validated using data from six worldwide sites including salt caverns and aquifers. Sites like Moss Bluff Clemens Dome and Spindletop (USA) scored highly while Teesside (UK) Lobodice (Czech Republic) and Beynes (France) were classified as unsuitable due to shallow depths and microbial activity. A software tool the UHSSI Calculator was developed to automate site evaluations. This approach offers a cost-effective tool for preliminary screening and supports the safer development of UHS.

Emissions from fossil fuel extraction conveyance and combustion are among the most significant causes of air pollution and climate change leading to arguably the most acute crises mankind has ever faced. The transition from fossil fuel-based energy systems to hydrogen is essential for meeting a portion of global decarbonization goals. Hydrogen offers certain features such as high gravimetric energy density that is required for heavy-duty shipping and freight applications and chemical properties such as high temperature combustion and reducing capabilities that are required for steel chemicals and fertilizer industries. However hydrogen that leaks has indirect climate implications stemming from atmospheric interactions that are emerging as a critical area of research. This study reviews recent literature on hydrogen’s global warming potential (GWP) highlighting its indirect contributions to radiative forcing via methane’s extended atmospheric lifetime tropospheric ozone formation and stratospheric water vapor formation. The 100-year GWP (GWP100) of hydrogen estimated to range between 8 and 12.8 underscores the need to minimize leakage throughout the hydrogen supply chain to maximize the climate benefits of using hydrogen instead of fossil fuels. Comparisons with methane reveal hydrogen’s shorter atmospheric lifetime and reduced long-term warming effects establishing it as a viable substitute for fossil fuels in sectors such as steel cement and heavy-duty transport. The analysis emphasizes the importance of accurate leakage assessments robust policy frameworks and advanced infrastructure to ensure hydrogen realizes its potential as a sustainable energy carrier that displaces the use of fossil fuels. Future research is recommended to refine climate models better understand atmospheric sinks and hydrogen leakage phenomena and develop effective strategies to minimize hydrogen emissions paving the way for environmentally sound use of hydrogen.

The transportation sector is a significant contributor to global carbon emissions thus necessitating a transition toward renewable energy sources (RESs) and electric vehicles (EVs). Among EV technologies fuel-cell EVs (FCEVs) offer distinct advantages in terms of refueling time and operational efficiency thus rendering them a promising solution for sustainable transportation. Nevertheless the integration of FCEVs in rural areas poses challenges due to the limited availability of refueling infrastructure and constraints in energy access. In order to address these challenges this study proposes a multi-objective energy management model for a hydrogen refueling station (HRS) integrated with RESs a battery storage system an electrolyzer (EL) a fuel cell (FC) and a hydrogen tank serving diverse FCEVs in rural areas. The model formulated using mixed-integer linear programming (MILP) optimizes station operations to maximize both cost and load factor performance. Additionally bi-directional trading with the power grid and hydrogen network enhances energy flexibility and grid stability enabling a more resilient and self-sufficient energy system. To the best of the authors’ knowledge this study is the first in the literature to present a multi-objective optimal management approach for grid-interactive renewablesupported HRSs serving hydrogen-powered vehicles in rural areas. The simulation results demonstrate that RES integration improves economic feasibility by reducing costs and increasing financial gains while maximizing the load factor enhances efficiency cost-driven strategies that may impact stability. The impact of the EL on cost is more significant while RES capacity has a relatively smaller effect on cost. However its influence on the load factor is substantial. The optimization of RES-supported hydrogen production has been demonstrated to reduce external dependency thereby enabling surplus trading and increasing financial gains to the tune of USD 587.83. Furthermore the system enhances sustainability by eliminating gasoline consumption and significantly reducing carbon emissions thus supporting the transition to a cleaner and more efficient transportation ecosystem.

The safe removal transportation and long-term storage of fuel debris in the decommissioning of Fukushima Daiichi is the biggest challenge facing Japan. In the nuclear power field passive autocatalytic recombiners (PARs) have become established as a technology to prevent hydrogen explosions inside the containment vessel. To utilize PAR as a measure to reduce the concentration of hydrogen generated in the fuel debris storage canister which is currently an issue it is required to perform in a sealed environment with high doses of radiation low temperature and high humidity and there are many challenges different from conventional PAR. A honeycombshaped catalyst based on automotive catalyst technology has been newly designed as a PAR and research has been conducted to solve unique problems such as high dose radiation low temperature high humidity coexistence of hydrogen and low oxygen and catalyst poisons. This paper summarizes the challenges of hydrogen generation in a sealed container the results of research and a guide to how to use the PAR for fuel debris storage canisters.

Proton exchange membrane water electrolyzers (PEMWEs) are a promising technology for green hydrogen production. However the adoption of PEMWE-based hydrogen production systems remains limited due to several challenges including high material costs limited performance and durability and difficulties in scaling the technology. Computational modeling serves as a powerful tool to address these challenges by optimizing system design improving material performance and reducing overall costs thereby accelerating the commercial rollout of PEMWE technology. Despite this conventional models often oversimplify key components such as porous transport and catalyst layers by assuming constant porosity and neglecting the spatial heterogeneity found in real electrodes. This simplification can significantly impact the accuracy of performance predictions and the overall efficiency of electrolyzers. This study develops a mathematical framework for modeling variable porosity distributions—including constant linearly graded and stepwise profiles—and derives analytical expressions for permeability effective diffusivity and electrical conductivity. These functions are integrated into a three-dimensional multi-domain COMSOL simulation to assess their impact on electrochemical performance and transport behavior. The results reveal that although porosity variations have minimal effect on polarization at low voltages they significantly influence internal pressure species distribution and gas evacuation at higher loads. A notable finding is that reversing stepwise porosity—placing high porosity near the membrane rather than the channel—can alleviate oxygen accumulation and improve current density. A multi-factor comparison highlights this reversed configuration as the most favorable among the tested strategies. The proposed modeling approach effectively connects porous media theory and systemlevel electrochemical analysis offering a flexible platform for the future design of porous electrodes in PEMWE and other energy conversion systems.

Green hydrogen produced through renewable energy sources is emerging as a pivotal element in global energy transitions. Despite its potential public acceptance remains a critical barrier to its large-scale implementation. This study aims to identify the socio-political and demographic determinants of public acceptance of green hydrogen. Using advanced variable selection methods including ridge lasso and elastic net regression we analyzed perceptions of climate change trust in government policies and demographic characteristics. The findings reveal that individuals prioritizing climate change over economic growth perceiving its impacts as severe and recognizing it as South Korea’s most pressing issue are more likely to accept green hydrogen. Trust in the government’s climate change response also emerged as a key factor. Demographic characteristics such as younger age higher income advanced education smaller family size and conservative political ideology were significantly associated with greater acceptance. These results highlight the importance of raising public awareness about the urgency of climate change and enhancing trust in government policies to promote societal acceptance of green hydrogen. Policymakers should consider these factors when developing strategies to advance the adoption of green hydrogen technologies and foster sustainable energy transitions.