Publications

Conventional fuels for vehicular applications generate hazardous pollutants which have an adverse effect on the environment. Therefore there is a high demand to shift towards environment-friendly vehicles for the present mobility sector. This paper highlights sustainable mobility and specifically sustainable transportation as a solution to reduce GHG emissions. Thus hydrogen fuel-based vehicular technologies have started blooming and have gained significance following the zero-emission policy focusing on various types of sustainable motilities and their limitations. Serving an incredible deliverance of energy by hydrogen fuel combustion engines hydrogen can revolution various transportation sectors. In this study the aspects of hydrogen as a fuel for sustainable mobility sectors have been investigated. In order to reduce the GHG (Green House Gas) emission from fossil fuel vehicles researchers have paid their focus for research and development on hydrogen fuel vehicles and proton exchange fuel cells. Also its development and progress in all mobility sectors in various countries have been scrutinized to measure the feasibility of sustainable mobility as a future. This paper is an inclusive review of hydrogen-based mobility in various sectors of transportation in particular fuel cell cars that provides information on various technologies adapted with time to add more towards perfection. When compared to electric vehicles with a 200-mile range fuel cell cars have a lower driving cost in all of the 2035 and 2050 scenarios. To stimulate the use of hydrogen as a passenger automobile fuel the cost of a hydrogen fuel cell vehicle (FCV) must be brought down to at least the same level as an electric vehicle. Compared to gasoline cars fuel cell vehicles use 43% less energy and generate 40% less CO2.

Due to there is no better way to exploit depleted gas reservoirs and hydrogen can generate from natural gas combustion. In this paper the possibility of in‐situ hydrogen generation in air injected gas reservoirs was determined through pseudo dynamic experiments. The study indicated that highertemperature and steam/methane ratio can generate more hydrogen and the temperature should not be lower than 600 °C within gas reservoirs. The debris has positive catalysis for hydrogen generation. The maximum mole fraction of hydrogen was 26.63% at 600 °C.

High-strength aluminum alloys are widely used in industry. Hydrogen embrittlement greatly reduces the performance and service safety of aluminum alloys. The hydrogen traps in aluminum profoundly affect the hydrogen embrittlement of aluminum. Here we took a coincidence-site lattice (CSL) symmetrically tilted grain boundary (STGB) Σ5(120)[001] as an example to carry out molecular dynamics (MD) simulations of hydrogen diffusion in aluminum at different temperatures and to obtain results and rules consistent with the experiment. At 700 K three groups of MD simulations with concentrations of 0.5 2.5 and 5 atomic % hydrogen (at. % H) were carried out for STGB models at different angles. By analyzing the simulation results and the MSD curves of hydrogen atoms we found that in the low hydrogen concentration of STGB models the grain boundaries captured hydrogen atoms and hindered their movement. In high-hydrogen-concentration models the diffusion rate of hydrogen atoms was not affected by the grain boundaries. The analysis of the simulation results showed that the diffusion of hydro-gen atoms at the grain boundary is anisotropic.

Decarbonisation of the energy sector is becoming increasingly more important to the reduction in climate change. Renewable energy is an effective means of reducing CO2 emissions but the fluctuation in demand and production of energy is a limiting factor. Liquid hydrogen allows for long-term storage of energy. Hydrogen quality is important for the safety and efficiency of the end user. Furthermore the quality of the hydrogen gas after liquefaction has not yet been reported. The purity of hydrogen after liquefaction was assessed against the specification of Hydrogen grade D in the ISO-14687:2019 by analysing samples taken at different locations throughout production. Sampling was carried out directly in gas cylinders and purity was assessed using multiple analytical methods. The results indicate that the hydrogen gas produced from liquefaction is of a higher purity than the starting gas with all impurities below the threshold values set in ISO-14687:2019. The amount fraction of water measured in the hydrogen sample increased with repeated sampling from the liquid hydrogen tank suggesting that the sampling system used was affected by low temperatures (−253 ◦C). These data demonstrate for the first time the impact of liquefaction on hydrogen purity assessed against ISO-14687:2019 showing that liquified hydrogen is a viable option for long-term energy storage whilst also improving quality.

The natural gas (NG) reforming is currently one of the low-cost methods for hydrogen production. However the mixture of H2 and CO2 in the produced gas inevitably includes CO2 and necessitates the costly CO2 separation. In this work a novel double chemical looping involving both combustion (CLC) and sorption-enhanced reforming (SE-CLR) was proposed towards the co-production of H2 and CO (CLC-SECLRHC) in two separated streams. CLC provides reactant CO2 and energy to feed SECLRHC which generates hydrogen in a higher purity as well as the calcium cycle to generate CO in a higher purity. Techno-economic assessment of the proposed system was conducted to evaluate its efficiency and economic competitiveness. Studies revealed that the optimal molar ratios of oxygen carrier (OC)/NG and steam/NG for reforming were recommended to be 1.7 and 1.0 respectively. The heat integration within CLC and SECLRHC units can be achieved by circulating hot OCs. The desired temperatures of fuel reactor (FR) and reforming reactor (RR) should be 850 °C and 600 °C respectively. The heat coupling between CLC and SECLRHC units can be realized via a jacket-type reactor and the NG split ratio for reforming and combustion was 0.53:0.47. Under the optimal conditions the H2 purity the H2 yield and the CH4 conversion efficiency were 98.76% 2.31 mol mol-1 and 97.96% respectively. The carbon and hydrogen utilization efficiency respectively were 58.60% and 72.45% in terms of the total hydrogen in both steam and NG. The exergy efficiency of the overall process reached 70.28%. In terms of the conventional plant capacity (75×103 t y-1 ) and current raw materials price (2500 $ t-1 ) the payback period can be 6.2 years and the IRR would be 11.5 demonstrating an economically feasible and risk resistant capability.

This study aimed to simulate the sector-coupled energy system of Germany in 2030 with the restriction on CO2 emission levels and to observe how the system evolves with decreasing emissions. Moreover the study presented an analysis of the interconnection between electricity heat and hydrogen and how technologies providing flexibility will react when restricting CO2 emissions levels. This investigation has not yet been carried out with the technologies under consideration in this study. It shows how the energy system behaves under different set boundaries of CO2 emissions and how the costs and technologies change with different emission levels. The study results show that the installed capacities of renewable technologies constantly increase with higher limitations on emissions. However their usage rates decreases with low CO2 emission levels in response to higher curtailed energy. The sector-coupled technologies behave differently in this regard. Heat pumps show similar behaviour while the electrolysers usage rate increases with more renewable energy penetration. The system flexibility is not primarily driven by the hydrogen sector but in low CO2 emission level scenarios the flexibility shifts towards the heating sector and electrical batteries.

The  understanding  of  physical  phenomena  occurring  during  the  refueling  of  H2  tanks  used for hydrogen mobility applications is the key point towards the most optimal refueling protocol. A lot of experimental investigations on tank refueling were performed in the previous years for different types and sizes of tank. Several operating conditions were tested through these experiments. For instance the HyTransfer project gave one of the major outputs on the understanding of the physical phenomena occurring during a tank refueling. From a numerical perspective the availability of accurate numerical tools is another key point. Such tools could be used instead of the experimental set-ups to test various operating conditions or new designs of tanks and injectors. The use of these tools can reduce the cost of the refueling protocol development in the future. However they first need to be validated versus experimental data. This work is dedicated to CFD (Computational Fluid Dynamics) modeling of the hydrogen refueling of a long horizontal 530L type IV tank. As of now the number of available CFD simulations for  such  a large  tank  is  low  as  the  computational  cost  is  significant  which  is  often considered as a bottleneck for this approach. The simulated operating conditions correspond to one of the  experimental  campaigns  performed  in  the  framework  of  the  HyTransfer  project. The  3D  CFD model is presented. In a first validation step the CFD results are compared with experimental data. Then  a  deeper  insight  into  the  physics  predicted  by  the  CFD  is  provided.   Finally  two  other methodologies  with  the  aim  to  reduce  the  computational  cost  have   been  tested.

In June 2021 the United States (US) Department of Energy (DOE) hosted the first-ever Hydrogen Shot Summit which lasted for two days. More than 3000 stockholders around the world were convened at the summit to discuss how low-cost clean hydrogen production would be a huge step towards solving climate change. Hydrogen is a dynamic fuel that can be used across all industrial sectors to lower the carbon intensity. By 2030 the summit hopes to have developed a means to reduce the current cost of clean hydrogen by 80%; i.e. to USD 1 per kilogram. Because of the importance of clean hydrogen towards carbon neutrality the overall DOE budget for Fiscal Year 2021 is USD 35.4 billion and the total budget for DOE hydrogen activities in Fiscal Year 2021 is USD 285 million representing 0.81% of the total DOE budget for 2021. The DOE hydrogen budget of 2021 is estimated to increase to USD 400 million in Fiscal Year 2022. The global hydrogen market is growing and the US is playing an active role in ensuring its growth. Depending on the electricity source used the electrolysis of hydrogen can have no greenhouse gas emissions. When assessing the advantages and economic viability of hydrogen production by electrolysis it is important to take into account the source of the necessary electricity as well as emissions resulting from electricity generation. In this study to evaluate the levelized cost of nuclear hydrogen production the International Atomic Energy Agency Hydrogen Economic Evaluation Program is used to model four types of LWRs: Exelon’s Nine Mile Point Nuclear Power Plant (NPP) in New York; Palo Verde NPP in Arizona; Davis-Besse NPP in Ohio; and Prairie Island NPP in Minnesota. Each of these LWRs has a different method of hydrogen production. The results show that the total cost of hydrogen production for Exelon’s Nine Mile Point NPP Palo Verde NPP Davis-Besse NPP and Prairie Island NPP was 4.85 ± 0.66 4.77 ± 1.36 3.09 ± 1.19 and 0.69 ± 0.03 USD/kg respectively. These findings show that among the nuclear reactors the cost of nuclear hydrogen production using Exelon’s Nine Mile Point NPP reactor is the highest whereas the cost of nuclear hydrogen production using the Prairie Island NPP reactor is the lowest.

Despite being the lightest element in the periodic table hydrogen poses many risks regarding its production storage and transport but it is also the one element promising pollutionfree energy for the planet energy reliability and sustainability. Development of such novel materials conveying a hydrogen source face stringent scrutiny from both a scientific and a safety point of view: they are required to have a high hydrogen wt.% storage capacity must store hydrogen in a safe manner (i.e. by chemically binding it) and should exhibit controlled and preferably rapid absorption–desorption kinetics. Even the most advanced composites today face the difficult task of overcoming the harsh re-hydrogenation conditions (elevated temperature high hydrogen pressure). Traditionally the most utilized materials have been RMH (reactive metal hydrides) and complex metal borohydrides M(BH4 )x (M: main group or transition metal; x: valence of M) often along with metal amides or various additives serving as catalysts (Pd2+ Ti4+ etc.). Through destabilization (kinetic or thermodynamic) M(BH4 )x can effectively lower their dehydrogenation enthalpy providing for a faster reaction occurring at a lower temperature onset. The present review summarizes the recent scientific results on various metal borohydrides aiming to present the current state-of-the-art on such hydrogen storage materials while trying to analyze the pros and cons of each material regarding its thermodynamic and kinetic behavior in hydrogenation studies.

Extensive decarbonisation efforts result in major changes in energy demand for the extractive industry. In 2021 the extraction and primary processing of metals and minerals accounted for 4.5 Gt of CO2 eq. per year. The aluminium industry was responsible for 1.1 Gt CO2 eq. direct and indirect emissions. To reach the European milestone of zero emissions by 2050 a reduction of 3% annually is essential. To this end the industry needs to take a turn towards less impactful production practices coupling secondary production with green energy sources. The present work aims to comprehensively compare the lifecycle energy consumption and environmental performance of a secondary aluminium smelter employing alternative thermal and electricity sources. In this frame a comparative analysis of the environmental impact of different thermal energy sources namely natural gas light fuel oil liquified petroleum gas hydrogen and electricity for a secondary aluminium smelter is presented. The results show that H2 produced by renewables (green H2 ) is the most environmentally beneficial option accounting for −84.156 kg CO2 eq. By producing thermal energy as well as electricity on site H2 technologies also serve as a decentralized power station for green energy production. These technologies account for a reduction of 118% compared to conventionally used natural gas. The results offer a comprehensive overview to aid decision-makers in comparing environmental impacts caused by different energy sources.