Hydrogen Loading Research Articles

Optimization of a standalone photovoltaic-based microgrid with electrical and hydrogen loads

Despite the ability of renewables to decarbonize energy use, their intermittent nature causes inconsistent energy generation, thus energy storage is required to tackle the supply-demand mismatch. While the use of hybrid battery-hydrogen energy storage for microgrids has been extensively studied, there is a lack of study on the integration of electricity and hydrogen supply systems. In other words, the concurrent targeting of hydrogen and electrical loads in a microgrid with hybrid battery-hydrogen storage is lacking. This study presents an optimization framework for the design and operation of a standalone microgrid with electrical and hydrogen loads. Two energy management strategies have been proposed and the optimization model is solved using particle swarm optimization algorithm. The proposed methodology was demonstrated through a case study and the levelized cost of energy ranges from 0.4551 USD/kWh to 0.4572 USD/kWh for the base case scenario. The optimal microgrid design in base case scenario is found to have a high value of potential energy waste possibility, indicating that the solar panel is oversized to reduce energy storage requirement. Sensitivity analysis results showed that a significant cost reduction can be achieved when only 95% of loads are targeted.

Techno-economic assessment and smart management of an integrated fuel cell-based energy system with absorption chiller for power, hydrogen, heating, and cooling in an electrified railway network

Nowadays, the transportation sector occupies a vital role in current society. However, this sector is the second-highest greenhouse gas emitter worldwide due to fossil fuel combustion. Transitioning from conventional to renewable energy propulsion is a promising alternative to climate change mitigation. This study proposes a smart decision-making approach of an integrated system assisted with renewable energy sources to satisfy the dynamic railway electrification demand. The proposed energy system consists of a proton-exchange membrane electrolyzer, solid-oxide fuel cell, and lithium-bromide absorption chiller assisted with solar radiation and wind turbine to simultaneously generate power, hydrogen, cooling, and heating loads. A novel approach consists of power-pinch analysis and multi-criteria decision-making (MCDM) to determine the optimal sizing of renewable resources considering the system's thermodynamic, economic, and exergy performance. A total of five optimal scenarios with different renewable sources share were obtained. Accordingly, the scenario with a share of 70/30 of solar and wind energy showed the highest competitiveness based on the MCDM. This scenario showed an energetic and exergetic efficiency of 49% and 34%, respectively. Furthermore, it yielded acceptable subproducts generation, including the production of 312.25 kg H2/day, in an economical budget with a levelized cost of energy (LCOE) value of 0.079 $/kWh.

Combined effects of temperature and of high hydrogen and oxygen contents on the mechanical behavior of a zirconium alloy upon cooling from the βZr phase temperature range

• Mechanical behavior of (prior-)β Zr upon cooling. • Hydrogen and oxygen contents up to 3000 wppm and 0.9 wt% respectively. • Tests at temperatures between 700 °C and 30 °C during cooling from 1000 °C to 1200 °C. • Strong synergic effects of hydrogen and oxygen contents and loading temperature. • Relationships proposed to describe the material mechanical behavior. During hypothetical loss-of-coolant accidents (LOCA), zirconium-based nuclear fuel claddings can be exposed to high temperatures in the β Zr phase domain and absorb substantial amounts of hydrogen (up to about 3000 weight ppm) and oxygen (up to about 1 weight %). This paper provides novel data about the combined effects of high hydrogen and oxygen contents on the mechanical behavior of the (prior-)β Zr phase, as a function of temperature, upon cooling from the β Zr phase temperature range. A protocol was developed to homogeneously charge Zircaloy-4 cladding tubes at different hydrogen contents, up to 3200 weight ppm, and oxygen contents, between 0.13 and 0.9 wt%. Tensile tests were then performed at various temperatures between 700 °C and 30 °C upon cooling from the β Zr domain. The results show that the mechanical behavior strongly depends on the testing temperature and the hydrogen and oxygen contents. Relationships are proposed to describe the macroscopic ductile-to-brittle transition and the mechanical behavior of the material as a function of temperature, hydrogen and oxygen contents. The predictions based on these relationships are compared to selected data from the literature obtained on claddings oxidized at high temperature, including results from semi-integral LOCA tests. Also, it is shown that considering the combined effects of hydrogen and oxygen is necessary to interpret the material's mechanical behavior, particularly the embrittlement of claddings subjected to LOCA-relevant secondary hydriding.

Study on waste heat measurement and composition change of Pd conductor after laser stimulation in H2 gas-loading system

This study mainly involves that palladium hydride with different gas-loading ratio is stimulated by YAG frequency doubling laser (λ=532nm) in H/Pd gas-loading system to produce excess heat. The range of hydrogen loading ratio of palladium hydride is 0 to 0.8. The results show that the waste heat is produced in the experiment stimulated by laser. When the hydrogen loading ratio in Pd is 0.3±0.01, the maximum waste heat produced by the system within 1 hour is about 120.91±0.47 J. Some new elements are produced on the surface of Pd samples, including Si, Al, Ca and some others, these elements were found in local locations by scanning electron microscopy and energy spectrum analysis. This suggests that some reactions may have taken place in the experiment.

Enhanced hydrogen generation from hydrolysis of MgLi doped with expanded graphite

Hydrolysis of Mg-based materials is considered as a potential means of safe and convenient real-time control of H2 release, enabling efficient loading, discharge and utilization of hydrogen in portable electronic devices. At present work, the hydrogen generation properties of MgLi-graphite composites were evaluated for the first time. The MgLi-graphite composites with different doping amounts of expanded graphite (abbreviated as EG hereinafter) were synthesized through ball milling and the hydrogen behaviors of the composites were investigated in chloride solutions. Among the above doping systems, the 10 wt.% EG-doped MgLi exhibited the best hydrogen performance in MgCl2 solutions. In particular, the 22 h-milled MgLi-10 wt.% EG composites possessed both desirable hydrogen conversion and rapid reaction kinetics, delivering a hydrogen yield of 966 mL H2 g−1 within merely 2 min and a maximum hydrogen generation rate of 1147 mL H2 min−1 g−1, as opposed to the sluggish kinetics in the EG-free composites. Moreover, the EG-doped MgLi showed superior air-stable ability even under a 75 RH% ambient atmosphere. For example, the 22 h-milled MgLi-10 wt.% EG composites held a fuel conversion of 89% after air exposure for 72 h, rendering it an advantage for Mg-based materials to safely store and transfer in practical applications. The similar favorable hydrogen performance of MgLi-EG composites in (simulate) seawater may shed light on future development of hydrogen generation technologies.

New Cage-Like Cerium Trihydride Stabilized at Ambient Conditions

New Cage-Like Cerium Trihydride Stabilized at Ambient Conditions

Synthesis of newly non-crystalline-porous- 2D-flakes- Mg(II) -methyl 3, 5-dinitro-salicylate complex for hydrogen storage

The present investigations are introducing simple strategy to synthesis a non-crystalline porous-2D-flakes of Mg(II)- methyl 3,5-dinitro-salicylate complex with large BET-surface area of ~788 m2g−1 via microwave assisted hydro-complexation. Structure visualization coupled with some of density function theory (DFT)-calculations are supported the proposal in which, Mg-ions are tetra-coordinated with two ligands of methyl 3, 5-dinitrosalicylate through four-oxygen-donor atoms with molar ratios of 1:2 as confirmed in structural analyses and other theoretical treatments. The produced Mg(II) -complex was characterized by micro-elemental analysis (C, H, N, O, M), Raman spectra, PXRD, TGA/DTA thermal analyses and Uv-Vis spectra. The produced 2D-flakes of Mg-complex is thermally stable and has melting point of ~312 °C, which is relatively high due to presence hydrogen bonding that, stabilize 2D-Mg-complex formation. Furthermore, ligands containing nitro-groups promote hydrogen loading (uptake) of Mg-complex through amino-formation, recording 4.7 wt% at 290 °C and H2-pressure of ~ 22 bar.

Development of test protocols for solid oxide electrolysis cells operated under accelerated degradation conditions

In order to be a real competitor to other industrial-scale hydrogen production technologies, solid oxide electrolysis cells (SOEC) must present essential features such as high hydrogen production rates, load flexibility and high system efficiency. However, operating conditions necessary to achieve these objectives can induce undesired performance deterioration and microstructural degradation negatively influencing the long-term stability of SOECs. This work provides the results of experimental investigations on the performance of SOECs operated under different operating conditions. In order to induce and accelerate specific degradation phenomena high steam partial pressures, fast load changes, high voltages, high steam conversion rates and alternating mode were applied. Different kinds and degrees of impact on performance and microstructure were observed and analyzed in detail. Correlations between performance changes and their underlying processes were investigated and useful connections between them were discovered. The major findings are summarized in the form of a suggestion for accelerated stress test (AST) protocols for SOECs. The developed ASTs enable deeper understanding of several degradation phenomena induced by different operating conditions and present methods for identification thereof. Further, the ASTs were estimated to have potential to predict performance changes over long-term operating periods.

Degradation of Titanium Sintered with Magnesium: Effect of Hydrogen Uptake

Multifunctional materials based on a combination of permanent and degradable metals open new perspectives for medical implants combining osseoconductivity and drug-delivery functions which can significantly decrease the number of implants’ revision. In this work, hybrid magnesium-titanium materials were produced via sintering, and the properties of the permanent titanium component before and after the degradation of the temporary magnesium part were evaluated. The changes of chemical composition and mechanical parameters were determined. Loading of hydrogen into the titanium part at room temperature was observed, which deteriorated the mechanical characteristics but could also simultaneously improve the biocompatibility of the permanent titanium implant. The control of degradation of the magnesium part and the modification of the titanium part are required for the development of partly degradable hybrid implants.

P2G 기반 마이크로그리드의 경제성 분석 및 보급 방안에 관한 연구

Recently, global interest in the hydrogen economy is increasing, and most advanced countries, as well as Korea, have established and implemented various policies to foster the hydrogen industry. Hydrogen is considered as an energy carrier that is able to integrate and control existing energy such as electricity, gas, and heat in one dimension, and theoretically, its possibility has already been confirmed. As the first step to implement this, advanced countries such as Switzerland and Germany are leading the development of Powr-to-Gas (P2G) technology. In Korea, some energy-related organizations are conducting various researches recently, and KEPCO (Korea Electric Power Corporation) began research to connect the P2G-based microgrid to the distribution grid in 2019. Currently, the design and construction of the demonstration site is in progress. In this paper, the economic feasibility of a P2G-based microgrid is analyzed and an appropriate direction of penetration is proposed considering the increase of hydrogen load. For the economic analysis, HOMER Pro, which is widely used worldwide for evaluating the economics of renewable energy and microgrids, is used and Bass" diffusion model is applied to predict the increase of hydrogen load. In the case study, the economic analysis is carried out to derive the optimal facility configuration for 10% of the total load of the Ulsan techno-industrial complex under construction of the P2G-based microgrid demonstration site. As well as the sensitivity according to the level of hydrogen load is evaluated for the purpose of utilization of unused energy caused by renewable energy.

Ab Initio Hydrogen Dynamics and the Morphology of Voids in Amorphous Silicon

This article presents an ab initio study of hydrogen dynamics inside nanometer‐size voids in amorphous silicon (a‐Si) within the framework of the density‐functional theory for a varying hydrogen load of 10–30 atoms per void at the low and high temperature of 400 and 700 K, respectively. Using the local density approximation (LDA) and its generalized‐gradient counterpart (GGA), the dynamics of hydrogen atoms inside the voids are examined with an emphasis on the diffusion of H atoms/molecules, and the resulting nanostructural changes of the void surfaces. The results from simulations suggest that the microstructure of the hydrogen distribution on the void surfaces and the morphology of the voids are characterized by the presence of a significant number of monohydride SiH bonds, along with a few dihydride configurations. The study also reveals that a considerable number (about 10–45 at%) of total H atoms inside a void can appear as H2 molecules for a hydrogen load of 10–30 H atoms per void. The approximate shape of the voids is addressed from a knowledge of the positions of the void‐surface atoms using the convex‐hull approximation and the Gaussian broadening of the pseudoatomic surfaces of Si and H atoms.

Controlling factors and mechanisms of fatigue crack growth influenced by high pressure of gaseous hydrogen in a commercially pure iron

This paper proposes an extended discussion of experimental results previously published by the authors and from literature about fatigue crack growth influenced by high pressure of gaseous hydrogen in a commercially pure iron. Firstly a summary of these results obtained for different exposure conditions in terms of gas pressure and loading frequency is presented. Two characteristic regimes, the first at low ΔK values characterized by a moderated fatigue crack growth enhancement and a nearly fully intergranular mode, and a highly-accelerated regime with a quasi-cleavage failure mode with the formation of coarse striations. The mechanisms controlling the different regimes of Hydrogen-Assisted Fatigue Crack Growth are discussed on the basis of observations of fracture surfaces and of deformation substructures within the plastic zone while assessing the capability of different models from literature to account for these observations. In a last section, the dependency of the transition between the different regimes as well as the crack growth rate enhancement in the highly-accelerated regime with respect to the hydrogen gas pressure and loading frequency is analyzed.

Study of hydrogen gaseous fuel influence on the thermal condition of a diesel engine

The current article presents experimental results for the thermal condition of a diesel-hydrogen powered engine. The object of the study is an air-cooled single cylinder diesel engine. A quantitative assessment of the engine thermal condition is made. It is based on four engine body part temperatures and the temperatures of exhaust gases and engine oil. The study is carried through by comparing the engine indexes via regulation characteristics as a function of the hydrogen mass content and load characteristics with constant hydrogen content. Experimental results as a function of engine speed at constant engine power are also presented. The data registered during the experiment is for two different diesel injection advance angles. A temperature for one location on the combustion chamber roof (cylinder head) is calculated. The results of the experiment are presented in charts.

(Invited) Rapid Photo-Charge Mapping of Stainless-Steel Under the Hydrogen Permeation

Photocurrent techniques have been applied to analyze the properties of passive films on metals and their corrosion phenomena. Photocurrent mapping is also used to evaluate the inhomogeneity of, for example, non-uniform corrosion behavior by using a lock-in amplifier to detect a weak photocurrent signal combined with a laser light scanning. This method is, however, takes a long time to acquire a scanning image due to a rather slow time-constant of the lock-in amplifier measurement. In this work, a photo-charge mapping method is developed in which an intense UV laser pulse light (405 nm, 0.5 W in the present study) is focused on the specimen surface and a photo-charge evolved by a single laser pulse is evaluated by integrating the photocurrent using an electronic integrator, as shown in Fig. 1. An intense laser pulse provides a large photocurrent in some condition sufficiently for a single photocurrent pulse analysis. Fast scanning of the laser light is also achieved by using a galvano-scanner. Currently, a time required for one image acquisition is a few minutes which is limited due to the software execution time. In this work, the spatial distribution of hydrogen permeation in a stainless-steel sheet (SUS304, 0.1 mm in thickness) placed in a Devanathan cell was traced under the tensile stress test. Hydrogen was introduced from the backside of the sheet by using the galvanostatic cathodic polarization at –1mA cm–2, and penetrated hydrogen to the front side was oxidized under the anodic polarization at +0.8 V vs. Ag-AgCl R.E. The passive film was pre-formed before the hydrogen penetration. Absorption of hydrogen into stainless steel caused a drastic increase of photocurrent on the n-type semiconductor passive film due to the photo-assisted oxidation of permeated hydrogen atom via a stainless-steel sheet, i.e., hydrogen atoms can be effectively oxidized by the holes generated by UV irradiation in the passive film. In the photo-charge image shown in Fig. 1, left half of the observed area (4mm x 4 mm, 40 x 40 pixel) was penetrated by hydrogen from the backside where the increase of photo-charge was observed. The Devanathan cell was combined with a tensile tester, and a photo-charge map was traced during the hydrogen loading under the loading condition until the notched sample was cleaved. The photo-charge intensity increased around the notch before cleavage, probably due to an increase of hydrogen concentration penetrated or thickening of the passive film. Figure 1

213 nm laser written waveguides in Ge-doped planar silica without hydrogen loading.

In this paper we present the first example of waveguides fabricated by UV writing in non-hydrogen loaded Ge-doped planar silica with 213 nm light. Single mode waveguides were fabricated and the numerical apertures and mode field diameters were measured for a range of writing fluences. A peak index change of 5.3 x 10-3 was inferred for the waveguide written with 70 kJ cm-2. The refractive index change is sufficient to match the index structure of standard optical fiber. Uniformity of the written structures was measured and a propagation loss of 0.39 ± 0.03 dB cm-1 was determined through cutback measurements.

Nanomaterial-mediated sustainable hydrogen supply induces lateral root formation via nitrate reductase-dependent nitric oxide

The supplementation of hydrogen gas (H2) has been found to favor the growth of plants, but long-term application of hydrogen-rich water (HRW) in agriculture is difficult due to low solubility and fast fugacity of hydrogen gas in water. Sustained release of hydrogen gas in plants is of significance but has not realized before. In this work, ammonia borane-loaded hollow mesoporous silica nanoparticle (AB@hMSN) is constructed to serve as a hydrogen-releasing nanomaterial for sustainable H2 supply in plants for a long time. AB@hMSN exhibiting high hydrogen loading capacity as well as sustained hydrogen releasing behavior in slightly acidic soil environments, sustainably supplys plentiful amounts of hydrogen gas in the root of tomato by penetrating into root cells. Tomato lateral root (LR) formation, one of major components of root system architecture, is remarkably induced by AB@hMSN-mediated H2 supply in a nitric oxide-dependent fashion. Further molecular evidences reveal that the influenced transcriptional levels of cell cycle-related genes, some miRNAs and their target genes in the auxin-responsive gene regulatory network are the important mechanisms underlying AB@hMSN-induced LR formation. Together, this report opens a new window for the application of hydrogen-releasing nanomaterials in agriculture.

Fiber Bragg gratings fabricated by femtosecond lasers for narrow-linewidth fiber laser

A narrow-linewidth erbium-doped fiber laser based on the fiber Bragg gratings (FBGs) fabricated was proposed and demonstrated experimentally. A pair of FBGs with reflectivity of 92 % and 10 %, respectively, at the center wavelength of 1580 nm were inscribed in standard SMF-28 fibers without hydrogen loading by femtosecond laser point-by-point directly writing method, which was used as mirrors for wavelength selection of fiber laser, gratings full width at half maximum (FWHM) was less than 0.15 nm. A simple linear-cavity fiber laser was realized based on gain medium, pump source and FBGs. When gain medium of Er-doped fiber is selected 8 m, a stable single wavelength of 1579 nm laser with a 3 dB linewidth of 0.06 nm was obtained. Its output power is 24.1 mW when the maximum pump power is 600 mA, and its single wavelength of 1579 nm is consistent with the central wavelength of the fabricated FBGs. This type of laser source shows real promise for applications in coherent optical frequency domain reflectometry and high resolution fiber sensor systems.

Performance analysis of a stand-alone polygeneration microgrid

Polygeneration Microgrids (PMG) are smart energy systems which can be configured for decentralised multiple outputs in the form of electricity, heat, cold, fuel (hydrogen) and drinking water. This paper presents an analysis of a stand-alone PMG, which caters to electrical, thermal and hydrogen loads. The stand-alone PMG consisting of solar photovoltaic field, fuel cell, solid state hydrogen storage and electrolyzer is modelled using commercial software HOMER. An hourly simulation is conducted to analyse its annual performance. A case study is carried out for a typical Indian village of about 50 households needing electrical energy of 100 kWh/day. The by-products of the optimized stand-alone PMG i.e., thermal energy and hydrogen, are quantified.

Reaction paths via a new transient phase in non-equilibrium hydrogen absorption of LaNi2Co3

This study investigated the non-equilibrium hydrogen absorption reaction paths of the AB5-type LaNi2Co3 alloy using time-resolved in situ synchrotron X-ray diffraction. Diffraction data were collected every second for reactions under two hydrogen loading pressures. Hydrogen absorption with a hydrogen loading of 1 MPa rapidly transformed α phase to a transient phase (estimated to be LaNi2Co3H3.1–3.6, named γ∗); this has not previously been observed under equilibrium processes. The γ∗ phase continuously transformed into the γ phase (LaNi2Co3H4.5–5.0), and the β phase (LaNi2Co3H~3.6) was not formed. When 0.18 MPa of hydrogen was loaded, initially, the γ∗ phase appeared, followed by the formation of the β phase, finally transforming into the γ phase. These results indicate that a higher loading pressure promotes the formation of the γ∗ phase and assists its continuous transformation into the γ phase by enhancing the dissolution of hydrogen into the α and γ∗ phases.

Swelling of Steel Film by Hydrogen Absorption at Cathodic Potential in Electrolyte

A 4-nm-thick alloy film with a metal composition close to AISI 304 stainless steel, deposited on a multilayer, was investigated by Jörg Zegenhagen and co-workers (article number 2000055) as a model of the stainless-steel surface region crucial for pitting corrosion. Using the X-ray standing wave method, the oxidation states of iron, chrome and nickel as well as film composition and changes after electrolyte exposure are resolved depth-selectively. Hydrogen loading by exposure to 0.1 M KCl at cathodic potential leads to swelling of the film by 11%, thus decreasing the resistance to pitting corrosion and finally leading to embrittlement.