Korea, Republic of

Hydrogen fuel cells have been installed in more than 100 facilities and numerous homes in Ulsan hydrogen town in the Republic of Korea. Despite the advantages of hydrogen accidents can still occur near residential areas. Thus appropriate risk mitigation plans should be established. In this study a computational fluid dynamics (CFD) model of natural and forced ventilation is presented as an emergency response to hydrogen leakages in pressure regulator equipment housing. The CFD model is developed and investigated using three vent configurations: UP CROSS and UP-DOWN. The simulation results indicate that the UPDOWN configuration achieves the lowest internal hydrogen concentration out of the three. In addition the relationship between the total vent size and internal hydrogen concentration is determined. A vent size of 12% of the floor area has the lowest hydrogen concentration. The use of nitrogen for forced ventilation during emergencies is proposed to ensure that the hydrogen concentration of the released gas is less than one-fourth of the lower flammability  2 / 25 limit of hydrogen. Compared to natural ventilation the time required to reach safe conditions is decreased when nitrogen forced ventilation is used.

In the present scenario much importance has been provided to hydrogen energy systems (HES) in the energy sector because of their clean and green behavior during utilization. The developments of novel techniques and materials have focused on overcoming the practical difficulties in the HES (production storage and utilization). Comparatively considerable attention needs to be provided in the hydrogen storage systems (HSS) because of physical-based storage (compressed gas cold/cryo compressed and liquid) issues such as low gravimetric/volumetric density storage conditions/parameters and safety. In material-based HSS a high amount of hydrogen can be effectively stored in materials via physical or chemical bonds. In different hydride materials Mg-based hydrides (Mg–H) showed considerable benefits such as low density hydrogen uptake and reversibility. However the inferior sorption kinetics and severe oxidation/contamination at exposure to air limit its benefits. There are numerous kinds of efforts like the inclusion of catalysts that have been made for Mg–H to alter the thermodynamic-related issues. Still those efforts do not overcome the oxidation/contamination-related issues. The developments of Mg–H encapsulated by gas-selective polymers can effectively and positively influence hydrogen sorption kinetics and prevent the Mg–H from contaminating (air and moisture). In this review the impact of different polymers (carboxymethyl cellulose polystyrene polyimide polypyrrole polyvinylpyrrolidone polyvinylidene fluoride polymethylpentene and poly(methyl methacrylate)) with Mg–H systems has been systematically reviewed. In polymer-encapsulated Mg–H the polymers act as a barrier for the reaction between Mg–H and O2/H2O selectively allowing the H2 gas and preventing the aggregation of hydride nanoparticles. Thus the H2 uptake amount and sorption kinetics improved considerably in Mg–H.

The hydrogen economy refers to an economic and industrial structure that uses hydrogen as its main energy source replacing traditional fossil-fuel-based energy systems. In particular the widespread adoption of hydrogen fuel cell vehicles (HFCVs) is one of the key factors enabling a hydrogen economy and aggressive investment in hydrogen refuelling infrastructure is essential to make large-scale adoption of HFCVs possible. In this study we address the problem of effectively designing a hydrogen supply network for refuelling HFCVs in urban areas relatively far from a large hydrogen production site such as a petrochemical complex. In these urban areas where mass supply of hydrogen is not possible hydrogen can be supplied by reforming city gas. In this case building distributed hydrogen production bases that extract large amounts of hydrogen from liquefied petroleum gas (LPG) or compressed natural gas (CNG) and then supply hydrogen to nearby hydrogen stations may be a cost-effective option for establishing a hydrogen refuelling infrastructure in the early stage of the hydrogen economy. Therefore an optimization model is proposed for effectively deciding when and where to build hydrogen production bases and hydrogen refuelling stations in an urban area. Then a case study of the southeastern area of Seoul known as a commercial and residential center is discussed. A variety of scenarios for the design parameters of the hydrogen supply network are analyzed based on the target of the adoption of HFCVs in Seoul by 2030. The proposed optimization model can be effectively used for determining the time and sites for building hydrogen production bases and hydrogen refuelling stations.

Hydrogen has been attracting attention as a fuel in the transportation sector to achieve carbon neutrality. Hydrogen storage in liquid form is preferred in locomotives ships drones and aircraft because these require high power but have limited space. However liquid hydrogen must be in a cryogenic state wherein thermal insulation is a core problem. Inner materials including glass bubbles multi-layer insulation (MLI) high vacuum and vapor-cooled shields are used for thermal insulation. An analytic study is preferred and proceeds liquid hydrogen tanks due to safety regulations in each country. This study reviewed the relevant literature for thermodynamic modeling. The literature was divided into static dynamic and systematic studies. In summary the authors summarized the following future research needs: The optimal design of the structure including suspension baffle and insulation system can be studied to minimize the boil-off gas (BOG). A dynamic study of the pressure mass flow and vaporizer can be completed. The change of the components arrangement from the conventional diesel–electric locomotive is necessary.

Since the 1970s hydrogen has been considered as a possible energy carrier for the storage of renewable energy. The main focus has been on addressing the ultimate challenge: developing an environmentally friendly successor for gasoline. This very ambitious goal has not yet been fully reached as discussed in this review but a range of new lightweight hydrogen-containing materials has been discovered with fascinating properties. State-of-the-art and future perspectives for hydrogen-containing solids will be discussed with a focus on metal borohydrides which reveal significant structural flexibility and may have a range of new interesting properties combined with very high hydrogen densities.

A study was performed to investigate the hydrogen embrittlement behavior of 18-Ni 300 maraging steel produced by selective laser melting and subjected to different heat treatment strategies. Hydrogen was pre-charged into the tensile samples by an electro-chemical method at the constant current density of 1 A m−2 and 50 A m−2 for 48 h at room temperature. Charged and uncharged specimens were subjected to tensile tests and the hydrogen concentration was eventually analysed using quadrupole mass spectroscopy. After tensile tests uncharged maraging samples showed fracture surfaces with dimples. Conversely in H-charged alloys quasi-cleavage mode fractures occurred. A lower concentration of trapped hydrogen atoms and higher elongation at fracture were measured in the H-charged samples that were subjected to solution treatment prior to hydrogen charging compared to the as-built counterparts. Isothermal aging treatment performed at 460 °C for 8 h before hydrogen charging increased the concentration of trapped hydrogen giving rise to higher hydrogen embrittlement susceptibility.

With the development of the hydrogen fuel cell automobile industry higher requirements are put forward for the construction of hydrogen energy infrastructure the matching of parameters and the control strategy of hydrogen filling rate in the hydrogenation process of hydrogenation station. Fuel for hydrogen fuel cell vehicles comes from hydrogen refueling stations. At present the technological difficulty of hydrogenation is mainly reflected in the balanced treatment of reducing the temperature rise of hydrogen and shortening the filling time during the fast filling process. The Joule-Thomson (JT) effect occurs when high-pressure hydrogen gas passes through the valve assembly which may lead to an increase in hydrogen temperature. The JT effect is generally reflected by the JT coefficient. According to the high pressure hydrogen in the pressure reducing valve the corresponding JT coefficients were calculated by using the VDW equation RK equation SRK equation and PR equation and the expression of JT effect temperature rise was deduced which revealed the hydrogen temperature variation law in the process of reducing pressure. Make clear the relationship between charging parameters and temperature rise in the process of decompression; the flow and thermal characteristics of hydrogen in the process of decompression are revealed. This study provides basic support for experts to achieve throttling optimization of related pressure control system in hydrogen industry

Solid-state hydrogen storage covers a broad range of materials praised for their gravimetric volumetric and kinetic properties as well as for the safety they confer compared to gaseous or liquid hydrogen storage methods. Among them AxBy intermetallics show outstanding performances notably for stationary storage applications. Elemental substitution whether on the A or B site of these alloys allows the effective tailoring of key properties such as gravimetric density equilibrium pressure hysteresis and cyclic stability for instance. In this review we present a brief overview of partial substitution in several AxBy alloys from the long-established AB5 and AB2-types to the recently attractive and extensively studied AB and AB3 alloys including the largely documented solid-solution alloy systems. We not only present classical and pioneering investigations but also report recent developments for each AxBy category. Special care is brought to the influence of composition engineering on desorption equilibrium pressure and hydrogen storage capacity. A simple overview of the AxBy operating conditions is provided hence giving a sense of the range of possible applications whether for low- or high-pressure systems.

It is now well established that electrochemical systems can optimally perform only within a narrow range of temperature. Exposure to temperatures outside this range adversely affects the performance and lifetime of these systems. As a result thermal management is an essential consideration during the design and operation of electrochemical equipment and can heavily influence the success of electrochemical energy technologies. Recently significant attempts have been placed on the maturity of cooling technologies for electrochemical devices. Nonetheless the existing reviews on the subject have been primarily focused on battery cooling. Conversely heat transfer in other electrochemical systems commonly used for energy conversion and storage has not been subjected to critical reviews. To address this issue the current study gives an overview of the progress and challenges on the thermal management of different electrochemical energy devices including fuel cells electrolysers and supercapacitors. The physicochemical mechanisms of heat generation in these electrochemical devices are discussed in-depth. Physics of the heat transfer techniques currently employed for temperature control are then exposed and some directions for future studies are provided.

This paper compares the well-to-wheel (WTW) greenhouse gas (GHG) emissions of representative vehicle types–internal combustion engine vehicle (ICEV) hybrid electric vehicle (HEV) plug-in hybrid electric vehicle (PHEV) battery electric vehicle (BEV) and fuel cell electric vehicle (FCEV)–in the future (2030) based on a WTW analysis for the present (2017) and an analysis of various energy policies that could affect future emissions. South Korea was selected as the target region because it has detailed energy policies related to alternative vehicles. The WTW analysis for the present was performed based on three sets of subordinate analyses: (1) life cycle analyses of eight base fuels; (2) life cycle analyses of electricity and hydrogen; and (3) analyses of the fuel economies of seven vehicle types. From the WTW analysis for the present the national average WTW GHG emissions of ICEV-gasoline ICEV-diesel ICEV-liquefied petroleum gas HEV PHEV BEV and FCEV were calculated as 225 233 201 159 133 109 and 55 g-CO₂-eq./km respectively. For calculating the WTW GHG emissions in the future two policies regarding electricity production and three policies regarding hydrogen production were analysed. Three cases with varying the degrees of improvements in fuel economies were considered. Six future scenarios were constructed and each scenario represented the case in which each energy policy is enacted. In the reference scenario for compact car the WTW GHG emissions of ICEVs-gasoline HEV PHEV BEV-200 mile FCEV were analysed as 161 110 97 86 and 91 g-CO₂-eq./km respectively. The differences between ICEV/HEV and BEV were predicted to decrease in the future mainly due to larger improvements of ICEV/HEV in fuel economies compared to that of BEV. The future life cycle GHG emissions of electricity and hydrogen were calculated according to energy policy. Both two policies regarding power generation were confirmed to increase the benefits of utilizing BEVs but current energy policy regarding hydrogen production were confirmed to decrease the benefits of utilizing FCEVs. Based on the comprehensive results of this study a framework was proposed to evaluate the impacts of an energy policy regarding electricity and hydrogen production on the benefits of using BEVs and FCEVs compared to using HEVs and ICEVs. This framework can also be utilized in other countries when they assess and establish their energy policies.

Plastic deformation and strain-induced martensite (SIM α′) transformation in metastable austenitic AISI 304 stainless steel were investigated through room temperature tensile tests at strain rates ranging from 2 × 10−6 to 2 × 10−2/s. The amount of SIM was measured on the fractured tensile specimens using a feritscope and magnetic force microscope. Elongation to fracture tensile strength hardness and the amount of SIM increased with decreasing the strain rate. The strain-rate dependence of RT tensile properties was observed to be related to the amount of SIM. Specifically SIM formed during tensile tests was beneficial in increasing the elongation to fracture hardness and tensile strength. Hydrogen suppressed the SIM formation leading to hydrogen softening and localized brittle fracture.

Many countries consider hydrogen as a promising energy source to resolve the energy challenges over the global climate change. However the potential of hydrogen explosions remains a technical issue to embrace hydrogen as an alternate solution since the Hindenburg disaster occurred in 1937. To ascertain safe hydrogen energy systems including production storage and transportation securing the knowledge concerning hydrogen flammability is essential. In this paper we addressed a comprehensive review of the studies related to predicting hydrogen flammability by dividing them into three types: experimental numerical and analytical. While the earlier experimental studies had focused only on measuring limit concentration recent studies clarified the extinction mechanism of a hydrogen flame. In numerical studies the continued advances in computer performance enabled even multi-dimensional stretched flame analysis following one-dimensional planar flame analysis. The different extinction mechanisms depending on the Lewis number of each fuel type could be observed by these advanced simulations. Finally historical attempts to predict the limit concentration by analytical modelling of flammability characteristics were discussed. Developing an accurate model to predict the flammability limit of various hydrogen mixtures is our remaining issue.

As part of the United Nations Global Technical Regulation No. 13 (UN GTR #13 [1]) vehicle fire safety is validated using a localized and engulfing fire test methodology and currently updates are being considered in the on-going Phase 2 development stage. The GTR#13 fire test is designed to verify the performance of a hydrogen storage system of preventing rupture when exposed to service-terminating condition of fire situation. The test is conducted in two stages – localized flame exposure at a location most challenging for thermally-activated pressure relief device(s) (TPRDs) to respond for 10 min. followed by engulfing fire exposure until the system vents and the pressure falls to less than 1 MPa or until “time out” (30min. for light-duty vehicle containers and 60 min. for heavy-duty vehicle containers). The rationale behind this two-stage fire test is to ensure that even when fire sizes are small and TPRDs are not responding the containers have fire resistance to withstand or fire sensitivity to respond to a localized fire to avoid system rupture. In this study appropriate fire sizes for localized and engulfing fire tests in GTR#13 are evaluated by considering actual fire conditions in a hydrogen-powered electric city bus. Quantitative risk analysis is conducted to develop various fire accident scenarios including regular bus fire battery fire and hydrogen leak fire. Frequency and severity analyses are performed to determine the minimum fire size required in GTR#13 fire test to ensure hydrogen storage tank safety in hydrogen-powered electric city buses.

Hydrogen as fuel has been considered as a feasible energy carry and which offers a clean and efficient alternative for transportation. During the high pressure filling the temperature in the hydrogen storage tank (HST) may rise rapidly due to the hydrogen compression. The high temperature may lead to safety problem. Thus for fast and safely refueling the hydrogen several key factors need to be considered. In the present study by the thermodynamics theories a mathematical model is established to simulate and analyze the high pressure filling process of the storage tank for the hydrogen station. In the analysis the physical parameters of normal hydrogen are introduced to make the simulation close to the actual process. By the numerical simulation for 50 MPa compressed hydrogen tank the temperature and pressure trends during filling are obtained. The simulation results for non-adiabatic filling were compared with the theoretically calculated ones for adiabatic conditions and the simulation results for non-adiabatic filling were compared with the simulation ones for adiabatic conditions. Then the influence of working pressure initial temperature mass flow rate initial pressure and inlet temperature on the temperature rise were analyzed. This study provides a theoretical research basis for high pressure hydrogen energy storage and hydrogenation technology.

Extensive energy consumption has become a major concern due to increase of greenhouse gas emissions and global warming. Hence hydrogen has attracted attention as a green fuel with zero carbon emission for green transportation through production of electric vehicles with hydrogen fuel cells. South Korea has launched a hydrogen society policy with the objective of expanding production of hydrogen from renewable energy sources. The hydrogen economy will play a critical role in reducing atmospheric pollution and global  arming. However new development of infrastructure for hydrogen refuelling and increasing awareness of the hydrogen economy is required together with reduced prices of hydrogen-driven vehicles that are promising options for a sustainable green  hydrogen economy.

In this study the environmental impacts of various alternative ship fuels for a coastal ferry were assessed by the life cycle assessment (LCA) analysis. The comparative study was performed with marine gas oil (MGO) natural gas and hydrogen with various energy sources for a 12000 gross tonne (GT) coastal ferry operating in the Republic of Korea (ROK). Considering the energy imports of ROK i.e. MGO from Saudi Arabia and natural gas from Qatar these countries were chosen to provide the MGO and the natural gas for the LCA. The hydrogen is considered to be produced by steam methane reforming (SMR) from natural gas with hard coal nuclear energy renewable energy and electricity in the ROK model. The lifecycles of the fuels were analyzed in classifications of Well-toTank Tank-to-Wake and Well-to-Wake phases. The environmental impacts were provided in terms of global warming potential (GWP) acidification potential (AP) photochemical potential (POCP) eutrophication potential (EP) and particulate matter (PM). The results showed that MGO and natural gas cannot be used for ships to meet the International Maritime Organization’s (IMO) 2050 GHG regulation. Moreover it was pointed out that the energy sources in SMR are important contributing factors to emission levels. The paper concludes with suggestions for a hydrogen application plan for ships from small nearshore ships in order to truly achieve a ship with zero emissions based on the results of this study.

Hydrogen (H2 ) is attracting attention as a renewable energy source in various fields. However H2 has a potential danger that it can easily cause a backfire or explosion owing to minor external factors. Therefore H2 gas monitoring is significant particularly near the lower explosive limit. Herein tin dioxide (SnO2 ) thin films were annealed at different times. The as-obtained thin films were used as sensing materials for H2 gas. Here the performance of the SnO2 thin film sensor was studied to understand the effect of annealing and operating temperature conditions of gas sensors to further improve their performance. The gas sensing properties exhibited by the 3-h annealed SnO2 thin film showed the highest response compared to the unannealed SnO2 thin film by approximately 1.5 times. The as-deposited SnO2 thin film showed a high response and fast response time to 5% H2 gas at 300 ◦C of 257.34% and 3 s respectively.

A district heating system is an eco-friendly power generation facility with high energy efficiency. The boiler water wall tube used in the district heating system is exposed to extremely harsh conditions and unexpected fractures often occur during operation. In this study a corrosion failure analysis of the boiler water wall tube was performed to elucidate the failure mechanisms. The study revealed that overheating by flames was the cause of the failure of the boiler water wall tube. With an increase in temperature in a localized region the microstructure not only changed from ferrite/pearlite to martensite/bainite which made it more susceptible to brittleness but it also developed tensile residual stresses in the water-facing side by generating cavities or microcracks along the grain boundaries inside the tube. High-temperature hydrogen embrittlement combined with stress corrosion cracking initiated many microcracks inside the tube and created an intergranular fracture.

The production and application of hydrogen an environmentally friendly energy source have been attracting increasing interest of late. Although steam methane reforming (SMR) method is used to produce hydrogen it is difficult to build a high-fidelity model because the existing equation-oriented theoretical model cannot be used to clearly understand the heat-transfer phenomenon of a complicated reforming reactor. Herein we developed an artificial neural network (ANN)-based data-driven model using 485710 actual operation datasets for optimizing the SMR process. Data preprocessing including outlier removal and noise filtering was performed to improve the data quality. A model with high accuracy (average R2 = 0.9987) was developed which can predict six variables through hyperparameter tuning of a neural network model as follows: syngas flow rate; CO CO2 CH4 and H2 compositions; and steam temperature. During optimization the search spaces for nine operating variables namely the natural gas flow rate for the feed and fuel hydrogen flow rate for desulfurization water flow rate and temperature air flow rate SMR inlet temperature and pressure and low-temperature shift (LTS) inlet temperature were defined and applied to the developed model for predicting the thermal efficiencies for 387420489 cases. Subsequently five constraints were established to consider the feasibility of the process and the decision variables with the highest process thermal efficiency were determined. The process operating conditions showed a thermal efficiency of 85.6%.

As the demand for eco-friendly energy increases hydrogen energy and liquid hydrogen storage technologies are being developed as an alternative. Hydrogen has a lower liquefaction point and higher thermal conductivity than nitrogen or neon used in general cryogenic systems. Therefore the application of hydrogen to cryogenic systems can increase efficiency and stability. This paper describes the design and analysis of a cryogenic cooling system for an electric propulsion system using liquid hydrogen as a refrigerant and energy source. The proposed aviation propulsion system (APS) consists of a hydrogen fuel cell a battery a power distribution system and a motor. For a lab-scale 5 kW superconducting motor using a 2G high-temperature superconducting (HTS) wire the HTS motor and cooling system were analyzed for electromagnetic and thermal characteristics using a finite element method-based analysis program. The liquid hydrogen-based cooling system consists of a pre-cooling system a hydrogen liquefaction system and an HTS coil cooling system. Based on the thermal load analysis results of the HTS coil the target temperature for hydrogen gas pre-cooling the number of buffer layers and the cryo-cooler capacity were selected to minimize the thermal load of the hydrogen liquefaction system. As a result the hydrogen was stably liquefied and the temperature of the HTS coil corresponding to the thermal load of the designed lab-scale HTS motor was maintained at 30 K.

Hydrogen gas storage place has been increasing daily because of its consumption. Hydrogen gas is a dream fuel of the future with many social economic and environmental benefits to its credit. However many hydrogen storage tanks exploded accidentally and significantly lost the economy infrastructure and living beings. In this study a protection wall under a worst-case scenario explosion of a hydrogen gas tank was analyzed with commercial software LS-DYNA. TNT equivalent method was used to calculate the weight of TNT for Hydrogen. Reinforced concrete and composite protection wall under TNT explosion was analyzed with a different distance of TNT. The initial dimension of the reinforced concrete protection wall was taken from the Korea gas safety code book (KGS FP217) and studied the various condition. H-beam was used to make the composite protection wall. Arbitrary-Lagrangian-Eulerian (ALE) simulation from LS-DYNA and ConWep pressure had a good agreement. Used of the composite structure had a minimum displacement than a normal reinforced concrete protection wall. During the worst-case scenario explosion of a hydrogen gas 300 kg storage tank the minimum distance between the hydrogen gas tank storage and protection wall should be 3.6 m.

The increasing global residential energy demand causes carbon emissions and ecological impacts necessitating cleaner efficient solutions. This study presents an innovative hybrid energy system integrating wind power and gas turbines for a four-story 16-unit residential building. The system generates electricity heating cooling and hydrogen using a Proton Exchange Membrane electrolyzer and a compression chiller. Integrating the electrolyzer enables hydrogen production and demonstrates hydrogen’s potential as a versatile clean energy carrier for systems contributing to advancements in hydrogen utilization. Simulations with Engineering Equation Solver software coupled with neural network-based multi-objective optimization fine-tuned parameters such as gas turbine efficiency wind turbine count and gas turbine inlet temperature to enhance exergy efficiency and reduce operational costs. The optimized system achieves an energy efficiency of 33.69% and an exergy efficiency of 36.95% and operates at $446.04 per hour demonstrating economic viability. It produces 51061 MWh annually exceeding the building’s energy demands and allowing surplus energy use elsewhere. BEopt simulations confirm the system meets residential needs by providing 2.52 GWh of electricity 3.36 GWh of heating and 5.11 GWh of cooling annually. This system also generates 10 kg of hydrogen per hour and achieves a CO₂ reduction of 10416 tons/year. The wind farm (25 turbines) provides most of the energy at 396.7 dollars per hour while the gas turbine operates at 80% efficiency. By addressing the challenges of intermittent renewable energy in residential Zero-Energy Buildings this research offers a scalable and environmentally friendly solution contributing to sustainable urban living and advancing hydrogen energy applications.

This study aims to elucidate the behavior of diffusible hydrogen and delayed fracture in martensitic steel with 1500 MPa strength during automotive painting process and under vehicle service conditions. A sequential process of automotive pretreatment line and vehicle service environment is simulated to evaluate the hydrogen pick up in each process. In case of the automotive painting line the absorption of hydrogen is within the common range in the process of phosphating treatment and electrodeposition. The baking process plays an effective role for desorbing the diffusible hydrogen absorbed during the automotive pre-treatment such as zinc-phosphating and electrodeposition process. In case of the corrosion environment under the automotive driving conditions hydrogen induced delayed fracture is accelerated as the exposure time increases. Further it is clarified that severe plastic deformation are the significant factors for hydrogen induced delayed fracture under with low pH value and present of chloride ion in a chemical solution parameter. In summary hydrogen is transported constantly during electrodeposition sequential line process of automobile manufacturing below the hydrogen content of 0.5 ppm which is not critical value for leading to hydrogen delayed fracture based on results of slow strain rate tensile tests. However exposure to extreme conditions under service environment of vehicle such as acidic solution and chloride chemistry solution that result in high level of hydrogen absorption severe plastic deformation in the sheared edge and constantly applied internal or external stresses can cause the hydrogen induced delayed fracture in the fully martensitic steels.

Rapid industrialization is consuming too much energy and non-renewable energy resources are currently supplying the world’s majority of energy requirements. As a result the global energy mix is being pushed towards renewable and sustainable energy sources by the world’s future energy plan and climate change. Thus hydrogen has been suggested as a potential energy source for sustainable development. Currently the production of hydrogen from fossil fuels is dominant in the world and its utilization is increasing daily. As discussed in the paper a large amount of hydrogen is used in rocket engines oil refining ammonia production and many other processes. This paper also analyzes the environmental impacts of hydrogen utilization in various applications such as iron and steel production rocket engines ammonia production and hydrogenation. It is predicted that all of our fossil fuels will run out soon if we continue to consume them at our current pace of consumption. Hydrogen is only ecologically friendly when it is produced from renewable energy. Therefore a transition towards hydrogen production from renewable energy resources such as solar geothermal and wind is necessary. However many things need to be achieved before we can transition from a fossil-fuel-driven economy to one based on renewable energy

The depletion of reliable energy sources and the environmental and climatic repercussions of polluting energy sources have become global challenges. Hence many countries have adopted various renewable energy sources including hydrogen. Hydrogen is a future energy carrier in the global energy system and has the potential to produce zero carbon emissions. For the non-fossil energy sources hydrogen and electricity are considered the dominant energy carriers for providing end-user services because they can satisfy most of the consumer requirements. Hence the development of both hydrogen production and storage is necessary to meet the standards of a “hydrogen economy”. The physical and chemical absorption of hydrogen in solid storage materials is a promising hydrogen storage method because of the high storage and transportation performance. In this paper physical hydrogen storage materials such as hollow spheres carbon-based materials zeolites and metal– organic frameworks are reviewed. We summarize and discuss the properties hydrogen storage densities at different temperatures and pressures and the fabrication and modification methods of these materials. The challenges associated with these physical hydrogen storage materials are also discussed.