Publications

Renewing a vision for European aviation: Europe today leads the world in civil aviation and air traffic management (ATM). This success should not be taken for granted particularly as the sector undergoes decarbonisation and digitalisation in today’s challenging geopolitical context. Significant value is at stake and capturing this value – for the sake of Europe’s competitiveness sustainability and sovereignty – is contingent on substantial investment in aviation research and innovation (R&I) and support to market uptake of new technologies to avoid the “valley of death” between technological development and product entry-into-service. Aviation is a major socio-economic contributor to Europe: The aviation industry is a vital component of Europe’s economy contri buting significantly to jobs gross domestic product (GDP) and trade. Overall the European aviation sector supports 15 million jobs and contributes EUR 1.1 trillion to European economic activity. The aviation sector is also critical to the EU single market European integration and global connectivity. It drives innovation and enhances Europe’s global influence and security through its combined focus on sustainability and competitiveness. The importance of aviation in achieving these fundamental goals for Europe is underscored by the findings of the Draghi report.

Indonesia’s energy sector faces critical challenges due to its heavy reliance on coal as the dominant power source which contributes to environmental degradation and rising CO2 emissions resulting into transition needs for renewable energy as targeted inside Nationally Determined Contribution (NDCs) 2060. In addition to these hydrogen energy also shows great potential for Indonesia’s energy needs. However to date there are no extensive research in Indonesia that simulate the effect of hydrogen incorporation and coal phase-out policy for 2050 power generation system making this research a critical contribution to the exploration of Indonesia's energy landscape. This study utilizes the Low Emissions Analysis Platform (LEAP). There are four simulated power generation scenarios in this study: the business-as-usual (BAU) scenario the hydrogen incorporation (HYD) scenario the coal phase-out (CPO) scenario and the progressive (PRO) scenario. The analysis indicates that the BAU scenario emerges as the most cost-effective approach for meeting Indonesia’s future electricity demand. However due to its inability to fulfill NDCs the CPO scenario is shown to be more viable from practical and cost perspectives requiring 406.9 GW capacity and USD 114.6 billion investment. On the contrary The HYD scenario largely aligns Indonesia’s hydrogen target potentially contributing 1-5% of energy demand and reducing coal reliance. Additionally while the PRO scenario has the highest investment cost (USD 151.4 billion) it also provides the lowest plant capacities (367.1 GW) offering the highest outputto-capacity ratio. The result suggests the necessity to enact government collaboration and construct feasibility analysis to implement renewable energy development.

Green hydrogen is critical for decarbonizing hard-to-electrify sectors but it faces high costs and investment risks. Here we defne and quantify the green hydrogen ambition and implementation gap showing that meeting hydrogen expectations will remain challenging despite surging announcements of projects and subsidies. Tracking 190 projects over 3 years we identify a wide 2023 implementation gap with only 7% of global capacity announcements fnished on schedule. In contrast the 2030 ambition gap towards 1.5 °C scenarios has been gradually closing as the announced project pipeline has nearly tripled to 422 GW within 3 years. However we estimate that without carbon pricing realizing all these projects would require global subsidies of US$1.3 trillion (US$0.8–2.6 trillion range) far exceeding announced subsidies. Given past and future implementation gaps policymakers must prepare for prolonged green hydrogen scarcity. Policy support needs to secure hydrogen investments but should focus on applications where hydrogen is indispensable.

Greenhouse gas anthropogenic emissions have triggered global warming with increasingly alarming consequences motivating the development of carbon-free energy systems. Hydrogen is proposed as an environmentally benign energy vector to implement this strategy but safe and efficient large-scale hydrogen storage technologies are still lacking to develop a competitive Hydrogen economy. LOHC (Liquid Organic Hydrogen Carrier) improves the storage and handling of hydrogen by covalently binding it to a liquid organic framework through catalytic exothermic hydrogenation and endothermic dehydrogenation reactions. LOHCs are oil-like materials that are compatible with the current oil and gas infrastructures. Nevertheless their high dehydrogenation enthalpy platinoid-based catalysts and thermal stability are bottlenecks to the emergence of this technology. In this review hydrogen storage technologies and in particular LOHC are presented. Moreover potential reactivities to design innovative LOHC are discussed.

Metal organic frameworks (MOFs) exhibit exceptional efficacy in hydrogen storage owing to their distinctive characteristics including elevated gravimetric densities rapid kinetics and reversibility. An in-depth look at existing literature indicates that while there are many studies using machine learning (ML) algorithms to develop predictive models for estimating hydrogen uptake by MOFs a great number of these models are not explainable. The novelty of this work lies in the integration of explainability approaches and ML models providing both accuracy and interpretability which is rarely addressed in existing studies. To fill this gap this paper attempts to develop explainable ML models for forecasting the hydrogen storage capacity of MOFs using three ML techniques including Bayesian regularized neural networks (BRANN) least squares support vector machines (LSSVM) and the extra tree algorithm (ET). An MOF databank comprising 1729 data points was assembled from literature. Surface area temperature pore volume and pressure were employed as input variables in this database. The findings demonstrate that of the three algorithms the ET intelligent model attained exceptional performance yielding precise estimates with a root mean square error (RMSE) of 0.1445 mean absolute error (MAE) of 0.0762 and a correlation coefficient (R2 ) of 0.995. In addition a novel contribution of this study is the generation of an explicit formula derived from BRANN enabling straightforward implementation of hydrogen storage predictions without requiring retraining of complex models. The sensitivity analysis employing Shapley Additive Explanation technique revealed that pressure and surface area were the most significant features influencing hydrogen storage with relevance values of 0.84 and 0.59 respectively. Furthermore the outlier detection evaluation using the leverage method showed that approximately 98 % of the utilized MOFs data are trustworthy and fell within the acceptable range. Altogether this work establishes a distinctive framework that combines accuracy interpretability and practical usability advancing the state of predictive modelling for hydrogen storage in MOFs.

The study provides a study on energy storage technologies for photovoltaic and wind systems in response to the growing demand for low-carbon transportation. Energy storage systems (ESSs) have become an emerging area of renewed interest as a critical factor in renewable energy systems. The technology choice depends essentially on system requirements cost and performance characteristics. Common types of ESSs for renewable energy sources include electrochemical energy storage (batteries fuel cells for hydrogen storage and flow batteries) mechanical energy storage (including pumped hydroelectric energy storage (PHES) gravity energy storage (GES) compressed air energy storage (CAES) and flywheel energy storage) electrical energy storage (such as supercapacitor energy storage (SES) superconducting magnetic energy storage (SMES) and thermal energy storage (TES)) and hybrid or multi-storage systems that combine two or more technologies such as integrating batteries with pumped hydroelectric storage or using supercapacitors and thermal energy storage. These different categories of ESS enable the storage and release of excess energy from renewable sources to ensure a reliable and stable supply of renewable energy. The optimal storage technology for a specific application in photovoltaic and wind systems will depend on the specific requirements of the system. It is important to carefully evaluate these needs and consider factors such as power and energy requirements efficiency cost scalability and durability when selecting an ESS technology.

As an energy carrier characterized by its high energy density and eco-friendliness hydrogen holds a pivotal position in energy transition. This paper elaborates on the scientific foundations and recent progress of photo- and electro-catalytic water splitting including the corresponding mechanism material design and optimization and the economy of hydrogen production. It systematically reviews the research progress in photo(electro)catalytic materials including oxides sulfides nitrides noble metals nonnoble metal and some novel photocatalysts and provides an in-depth analysis of strategies for optimizing these materials through material design component adjustment and surface modification. In particular it is pointed out that nanostructure regulation dimensional engineering defect introduction doping alloying and surface functionalization can remarkably improve the catalyst performance. The importance of adjusting reaction conditions such as pH and the addition of sacrificial agents to boost catalytic efficiency is also discussed along with a comparison of the cost-effectiveness of different hydrogen production technologies. Despite the significant scientific advancements made in photo(electro)catalytic water splitting technology this paper also highlights the challenges faced by this field including the development of more efficient and stable photo(electro)catalysts the improvement of system energy conversion efficiency cost reduction the promotion of technology industrialization and addressing environmental issues.

Hydrogen energy is valued for its diverse sources and clean low-carbon nature and is a promising secondary energy source with wide-ranging applications and a significant role in the global energy transition. Nonetheless hydrogen’s low energy density makes its largescale storage and transport challenging. Liquid hydrogen with its high energy density and easier transport offers a practical solution. This study examines the global hydrogen liquefaction methods with a particular emphasis on the liquid nitrogen pre-cooling Claude cycle process. It also examines the factors in the helium refrigeration cycle—such as the helium compressor inlet temperature outlet pressure and mass—that affect energy consumption in this process. Using HYSYS software the hydrogen liquefaction process is simulated and a complete process system is developed. Based on theoretical principles this study explores the pre-cooling refrigeration and normal-to-secondary hydrogen conversion processes. By calculating and analyzing the process’s energy consumption an optimized flow scheme for hydrogen liquefaction is proposed to reduce the total power used by energy equipment. The study shows that the hydrogen mass flow rate and key helium cycle parameters—like the compressor inlet temperature outlet pressure and flow rate—mainly affect energy consumption. By optimizing these parameters notable decreases in both the total and specific energy consumption were attained. The total energy consumption dropped by 7.266% from the initial 714.3 kW and the specific energy consumption was reduced by 11.94% from 11.338 kWh/kg.

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.

The use of hydrogen as fuel presents many safety challenges due to its flammability and explosive nature combined with its lack of color taste and odor. The purpose of this paper is to present an electrochemical sensor that can achieve rapid and accurate detection of hydrogen leakage. This paper presents both the component elements of the sensor like sensing material sensing element and signal conditioning as well as the electronic protection and signaling module of the critical concentrations of H2. The sensing material consists of a catalyst type Vulcan XC72 40% Pt from FuelCellStore (Bryan TX USA). The sensing element is based on a membrane electrode assembly (MEA) system that includes a cathode electrode an ion-conducting membrane type Nafion 117 from FuelCellStore (Bryan TX USA). and an anode electrode mounted in a coin cell type CR2016 from Xiamen Tob New Energy Technology Co. Ltd (Xiamen City Fujian Province China). The electronic block for electrical signal conditioning which is delivered by the sensing element uses an INA111 from Burr-Brown by Texas Instruments Corporation (Dallas TX USA). instrumentation operational amplifier. The main characteristics of the electrochemical sensor for hydrogen leakage detection are operation at room temperature so it does not require a heater maximum amperometric response time of 1 s fast recovery time of maximum 1 s and extended range of hydrogen concentrations detection in a range of up to 20%.