Germany

Importing renewable energy to Europe may offer many potential benefits including reduced energy costs lower pressure on infrastructure development and less land use within Europe. However open questions remain: on the achievable cost reductions how much should be imported whether the energy vector should be electricity hydrogen or derivatives like ammonia or steel and their impact on Europe’s infrastructure needs. This study integrates a global energy supply chain model with a European energy system model to explore net-zero emission scenarios with varying import volumes costs and vectors. We find system cost reductions of 1-10% within import cost variations of ± 20% with diminishing returns for larger import volumes and a preference for methanol steel and hydrogen imports. Keeping some domestic power-to-X production is beneficial for integrating variable renewables leveraging local carbon sources and power-to-X waste heat. Our findings highlight the need for coordinating import strategies with infrastructure policy and reveal maneuvering space for incorporating non-cost decision factors.

South Africa has excellent conditions for renewable energy generation making it well placed to produce green hydrogen for both domestic use and export. In building a green hydrogen economy around export markets it will face competition from countries with equivalent or better resources and/or that are located closer to export markets (e.g. in North Africa and the Middle East) or have lower capital costs (developed markets like Australia and Canada). South Africa however has an extensive energy system with unserved electricity demand. The ability to trade electricity with the national grid (feeding into the grid during times of peak dedicated renewable energy supply and extracting from the grid during times of low dedicated renewable energy availability) could reduce the cost of producing green hydrogen by as much as 10–25 %. This paper explores the opportunity for South African green hydrogen producers presented by the electricity supply crisis that has been ongoing since 2007. It highlights the potential for a mutually reinforcing growth cycle between renewable energy and green hydrogen to be established which will contribute not only to the mitigation of greenhouse gas emissions but to the local economy and broader society.

Given the economic industrial and environmental value of green dihydrogen (H2) optimization of water electrolysis as a means of producing H2 is essential. Binders are a crucial component of electrocatalysts yet they remain largely underdeveloped with a significant lack of standardization in the field. Therefore targeted research into the development of alternative binder systems is essential for advancing performance and consistency. Binders essentially act as the key to regulating the electrode (support)–catalyst–electrolyte interfacial junctions and contribute to the overall reactivity of the electrocatalyst assembly. Therefore alternative binders were explored with a focus on cost efficiency and environmental compatibility striving to achieve desirable activity and stability. Herein the alkaline hydrogen evolution reaction (HER) was investigated and the sluggish water dissociation step was targeted. Controlled hydrophilic poly(vinyl alcohol)-based hydrogel binders were designed for this application. Three hydrogel binders were evaluated without incorporated electrocatalysts namely PVA145 PVA145-blend-bPEI1.8 and PVA145-blend-PPy. Interestingly the study revealed that the hydrophilicity of the binders exhibited an enhancing effect on the observed activity resulting in improved performance compared to the commercial binder Nafion™. Notably the PVA145 system stands out with an overpotential of 224 mV at−10 mA·cm−2 (geometric) in 1.0 M KOH compared to the 238 mV exhibited by Nafion™. Inclusion of Pt as active material in PVA145 as binder exhibited a synergistic increase in performance achieving a mass activity of 1.174 A.cm−2.mg−1 Pt in comparison to Nafion™’s 0.344 A.cm−2.mg−1 Pt measured at−150 mV vs RHE. Our research aimed to contribute to the development of cost-effective and efficient binder systems stressing the necessity to challenge the dominance of the commercially available binders.

Fuel cell vehicles (FCVs) represent an intriguing alternative to battery electric vehicles (BEVs). While the acceptance of BEVs has been widely discussed acceptance-based recommendations for promoting adoption of FCVs remain ambiguous. This paper aims to improve our understanding by reporting results from a pioneer study based on the standardized Unified Theory of Acceptance and Use of Technology 2 (UTAUT2). The sample consists of n1 = 258 registered customers of H2mobility in Germany. For effect control another n2 = 294 participant sample was drawn from the baseline population. Data were analyzed using SmartPLS 4 and importance-performance mapping (IPMA). Results demonstrate that FCV acceptance primarily relies on Perceived Usefulness Perceived Conditions and Normative Influence while surprisingly hypotheses involving Perceived Risk and Green Attitude are rejected. Finally a discussion reveals ways to increase the level of public acceptance. Three practical strategies emerge. For future acceptance analyses the authors suggest incorporating the young concept of ‘societal readiness’.

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.

The chemical industry faces major challenges worldwide. Since 1950 production has increased 50-fold and is projected to continue growing particularly in Asia. It is one of the most energy- and resource-intensive industries contributing significantly to greenhouse gas emissions and the depletion of finite resources. This development exceeds planetary boundaries and calls for a sustainable transformation of the industry. The key transformation areas are as follows: (1) Non-Fossil Energy Supply: The industry must transition away from fossil fuels. Renewable electricity can replace natural gas while green hydrogen can be used for high-temperature processes. (2) Circularity: Chemical production remains largely linear with most products ending up as waste. Sustainable product design and improved recycling processes are crucial. (3) Non-Fossil Feedstock: To achieve greenhouse gas neutrality oil gas and coal must be replaced by recycling plastics renewable biomaterials or CO2-based processes. (4) Sustainable Chemical Production: Energy and resource savings can be achieved through advancements like catalysis biotechnology microreactors and new separation techniques. (5) Sustainable Chemical Products: Chemicals should be designed to be “Safe and Sustainable by Design” (SSbD) meaning they should not have hazardous properties unless essential to their function. (6) Sufficiency: Beyond efficiency and circularity reducing overall material flows is essential to stay within planetary boundaries. This shift requires political economic and societal efforts. Achieving greenhouse gas neutrality in Europe by 2050 demands swift and decisive action from industry governments and society. The speed of transformation is currently too slow to reach this goal. Science can drive innovation but international agreements are necessary to establish a binding framework for action.

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.

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.

Emerging energy technologies offer significant opportunities for climate change mitigation. However the assessment of their potential environmental impact through prospective life cycle assessment (pLCA) is challeng‑ ing owing to parameter uncertainties arising from data gaps temporal variability and evolving technological contexts when modeling their prospective life cycle inventories (pLCI). Existing methodologies lack standardized approaches for systematically integrating parameter uncertainty within pLCI frameworks often initially overlooking it. In order to fill this gap this study proposes a structured and transparent approach for incorporating parameter uncertainty directly into the pLCI modeling process. The goal is to enhance the robustness transparency and reproducibility of pLCI models. A decision–support flowchart based on an adapted six-step framework was developed to help life cycle assessment (LCA) practitioners address parameter uncertainty during the “goal and scope definition” and“life cycle inventory” phases of pLCA. The flowchart guides users through the process of defining of the assessment’s goal scope as well as its temporal and geographical boundaries and the technology’s maturity level (Step 1). Step 2 entails gathering data to depict the technology’s development. Steps 3 and 4 involve identifying parameters that are likely to change in the future such as manufacturing processes materials equipment and component dimensions as well as their respective uncertainties. Step 5 includes the learning effects required for industrial-scale production once the technology has reached maturity. Finally step 6 identifies external developments impacting the technology as well as contributing uncertainties. A case study of a fuel cell-based propulsion system for a hydrogen-powered aircraft in 2040 illustrates the applicability of the framework. This study introduces a structured flowchart to support decision making in cases when parameter uncertainty should be integrated into pLCI modeling. By supporting the selection of appropriate prospective meth‑ ods as well as uncertainty identification and characterization strategies the proposed flowchart enhances the trans‑ parency consistency and representativeness of the pLCA results facilitating their broader application in emerging technology assessment methods.

Green hydrogen is essential for advancing the energy transition as it is regarded as a CO2-neutral flexible and storable energy carrier. Particularly in steel production which is known for its high energy intensity hydrogen has great potential to replace conventional energy sources. In a game-theoretic bi-level optimization model involving a power plant operator and a steel company we investigate in which situations the production and use of green hydrogen is advantageous from an economic and ecological point of view. Through an extensive case study based on a realworld scenario we can observe that hydrogen production can serve as a profitable and flexible secondary income opportunity for the power plant operator and help avoid curtailment and spot market losses. On the other hand the steel manufacturer can reduce CO2 emissions and associated costs while also meeting the growing customer demand for low-carbon products. However our findings also highlight important trade-offs and uncertainties. While lower electricity generation costs or improved electrolyzer efficiency enhance hydrogen’s competitiveness increases in coal and CO2 emission prices do not always result in greater hydrogen adoption. This is due to the persistent reliance on a non-replaceable share of coal in steel production which raises the overall cost of both low-carbon and carbon-intensive steel. The model further shows that consumer demand elasticity plays a critical role in determining hydrogen uptake. These insights underscore the importance of not only reducing hydrogen costs but also designing supportive policies that address market acceptance and the full cost structure of green industrial products.

High-temperature proton exchange membrane fuel cells (HT-PEM FCs) represent a promising avenue for generating carbon dioxide-free electricity through the utilization of hydrogen fuel. These systems present numerous advantages and challenges for mobile applications positioning them as pivotal technologies for the realization of emission-free regional aircraft. Efficient thermal management of such fuel cell-powered systems is crucial for ensuring the safe and durable operation of the aircraft while concurrently optimizing system volume mass and minimizing parasitic energy consumption. This paper presents four distinct heat transfer principles tailored for the FC-system of a conceptual hydrogen-electric regional aircraft exemplified by DLR’s H2ELECTRA. The outlined approaches encompass conductive cooling air cooling liquid cooling phase change cooling and also included is the utilization of liquid hydrogen as a heat sink. Approaches are introduced with schematic cooling architectures followed by a comprehensive evaluation of their feasibility within the proposed drivetrain. Essential criteria pertinent to airborne applications are evaluated to ascertain the efficacy of each thermal management strategy. The following criteria are selected for evaluation: safety ease of integration reliability and life-cycle costs technology readiness and development as well as performance which is comprised of heat transfer weight volume and parasitic power consumption. Of the presented cooling methods two emerged to be functionally suitable for the application in MW-scale aircraft applications at their current state of the art: liquid cooling utilizing water under high pressure or other thermal carrier liquids and phase-change cooling. Air cooling and conductive cooling have a high potential due to their reduced system complexity and mass but additional studies investigating effects at architecture level in large-scale fuel cell stacks are needed to increase performance levels. These potentially suitable heat transfer technologies warrant further investigation to assess their potential for complexity and weight reduction in the aircraft drivetrain.