Hydrogen Storage

Since 1990, there has been an ongoing collaboration among the authors in the three laboratories to (1) prepare alloys of the AB(sub 5) and AB(sub 2) types, using arc-melting/annealing and mechanical alloying/annealing techniques; (2) examine their physico-chemical characteristics (morphology, composition); (3) determine the hydrogen absorption/desorption behavior (pressure-composition isotherms as a function of temperature); and (4) evaluate their performance characteristics as hydride electrodes (charge/discharge, capacity retention, cycle life, high rate capability). The work carried out on representative AB(sub 5) and AB(sub 2) type modified alloys (by partial substitution or with small additives of other elements) is presented. The purpose of the modification was to optimize the thermodynamics and kinetics of the hydriding/dehydriding reactions and enhance the stabilities of the alloys for the desired battery applications. The results of our collaboration, to date, demonstrate that (1) alloys prepared by arc melting/annealing and mechanical alloying/annealing techniques exhibit similar morphology, composition and hydriding/dehydriding characteristics; (2) alloys with the appropriate small amounts of substituent or additive elements: (1) retain the single phase structure, (2) improve the hydriding/dehydriding reactions for the battery applications, and (3) enhance the stability in the battery environment; and (3) the AB(sub 2) type alloys exhibit higher energy densities than the AB(sub 5) type alloys but the state-of-the-art, commercialized batteries are predominantly manufactured using Ab(sub 5) type alloys.

The notion of dominant designs deals with dominance in the market and the dominant design is thought to be dominant because of market selection forces. The notion thus ignores the possible selection that takes place in pre-market R&D stages of technological trajectories. In this paper we ask the question whether pre-market selection takes place and if this can lead to

This paper discusses the possibility of extraction of Hydrogen from urine and using it as a fuel to power various machinery and automobiles which could run on hydrogen fuel. The paper also attempts to show a practical layout of various processes and stages which could facilitate the conversion of urea into hydrogen molecules which can be then stored in compressed chambers and subsequently distributed as required. The design is compact, user-friendly, sustainable and is mostly based on domestic use.

This paper gives an overview of the opportunities that exist for the combination of stochastic power generation and hydrogen production, storage and end-use. It is described how hydrogen storage can be applied in both isolated and grid-connected systems, and how the produced hydrogen can be utilized for stationary energy supply and as a fuel for transportation. The paper discusses the benefits and limitations of the different hydrogen storage applications, and emphasizes the need for stochastic studies both for long-term planning and operation planning. A simulation case study of using excess wind power in a weak grid to produce hydrogen for vehicles has been presented. It is shown that the penetration of wind power can be significantly increased by introducing electrolytic hydrogen production as a controllable load

Modern photovoltaic systems wholesaling on Chinese marketplaces such as Alibaba sell for as little as $0.18/watt from RISEN ENERGY CO., LTD for monocrystalline architecture. Degradation rates are typically around 15% for 20 years, or around 0.8% per anum. That means a 1 kW system will produce 84% of its original power output after two decades. Panel type: 275-280/330-335W Multi-Module Price per watt (USD): 0.28 High, 0.175 Low, 0.185 Average. The average price for 350-watt panels is 18.5 cents per watt. The second major cost input is the DC/AC converter. Using data from Alibaba, numerous products were sampled. The most cost-competitive DC/AC rectifiers were ones used for solar-powered well water pumps. 7.5 kW units were priced around $250, yielding a price per kilowatt of $34. In our case, we only need a DC-DC converter, stepping down the voltage from the panel peak of around 35 to 12 for the electrolyzer. DC/DC converters are roughly the same price as DC/AC inverters. The Levelized Cost of Energy (LCOE) is determined by the irradiance available much more so than it is by slight differences in the panel module costs. A solar array in Scotland (880 kWh/kWp/yr) won't be nearly as cheap as one in Chile (2300 kWh/kWp/yr), or in Los Vegas (1900 kWh/kWp/yr). With the availability of low-cost photovoltaic energy without the need for balancing grid requirements, the need for storage is eliminated, this opens up the possibility of producing ultra-low cost hydrogen below the price of methane reforming. Hydrogen on its own is virtually useless, it has virtually no application as a fuel, thus we are forced to turn to ammonia. Until ammonia begins its use as a low-emission fuel in the near future, the fertilizer market is the biggest opportunity for disruption. Rather than purchasing

The lattice constants a and c of the as cast hexagonal (C14) Laves phase TiCr1.78-xMnx (x=0, 0.4, 0.6 and 0.8) have been measured by X-ray diffraction at room temperature as a function of the Mn content. It has been found that a decreases with increasing x while c remains almost unchanged. Being this alloy interesting as material for solid state hydrogen storage, pressure-composition isotherms have been traced on desorption mode for the H2 gas pressure and temperature varying from 10 to 0.01 MPa and from 209 to 307 K, respectively. From the temperature dependence of the plateau pressure the molar quantities ΔH and ΔS associated with the hydride decomposition have been determined as a function of the Mn content. With increasing x, both ΔH and ΔS progressively decrease, and the desorption pressure initially decreases (for x ≤ 0.4) then slightly increases. At the same time, the pseudo-plateaus become flatter.

The article gives a comprehensive overview of hydrogen storage in carbon nanostructures, including experimental results and theoretical calculations. Soon after the discovery of carbon nanotubes in 1991, different research groups succeeded in filling carbon nanotubes with some elements, and, therefore, the question arose of filling carbon nanotubes with hydrogen by possibly using new effects such as nano-capillarity. Subsequently, very promising experiments claiming high hydrogen storage capacities in different carbon nanostructures initiated enormous research activity. Hydrogen storage capacities have been reported that exceed the benchmark for automotive application of 6.5 wt% set by the U.S. Department of Energy. However, the experimental data obtained with different methods for various carbon nanostructures show an extreme scatter. Classical calculations based on physisorption of hydrogen molecules could not explain the high storage capacities measured at ambient temperature, and, assuming chemisorption of hydrogen atoms, hydrogen release requires temperatures too high for technical applications. Up to now, only a few calculations and experiments indicate the possibility of an intermediate binding energy. Recently, serious doubt has arisen in relation to several key experiments, causing considerable controversy. Furthermore, high hydrogen storage capacities measured for carbon nanofibers did not survive cross-checking in different laboratories. Therefore, in light of today's knowledge, it is becoming less likely that at moderate pressures around room temperature carbon nanostructures can store the amount of hydrogen required for automotive applications.

This work deals with the investigations of hydrogen adsorption energies of the Li functionalized Covalent Organic Framework-366 (COF-366) by using the density functional theory method. Based on total energy calculations, it was found that Li atom is preferentially trapped at the center site of the tetra (p-amino-phenyl) porphyrin and the onN site of a terephthaldehyde chain. Moreover, hydrogen adsorption energies per H2 for 1e3 H2 loadings range from 0.03 to 0.22 eV. According to ab initio molecular dynamics simulations, our results found that hydrogen capacities of Li functionalized COF-366 at ambient pressure are 2.06, 1.58, and 1.05 wt% for 77, 150 and 298 K, respectively.

There is a need for numerical models capable of predicting local accumulation of hydrogen near stress con-centrators and crack tips to prevent and mitigate hydrogen assisted fracture in steels. The experimental char-acterisation of trapping parameters in metals, which is required for an accurate simulation of hydrogen transport, is usually performed through the electropermeation test. In order to study grain size influence and grain boundary trapping during permeation, two modelling approaches are explored; a 1D Finite Element model including trap density and binding energy as input parameters and a polycrystalline model based on the assignment of a lower diffusivity and solubility to the grain boundaries. Samples of pure iron after two different heat treatments-950 • C for 40 min and 1100 • C for 5 min-are tested applying three consecutive rising permeation steps and three decaying steps. Experimental results show that the finer grain microstructure promotes a diffusion delay due to grain boundary trapping. The usual methodology for the determination of trap densities and binding energies is revisited in which the limiting diluted and saturated cases are considered. To this purpose, apparent diffusivities are fitted including also the influence of boundary conditions and comparing results provided by the constant concentration with the constant flux assumption. Grain boundaries are char-acterised for pure iron with a binding energy between 37.8 and 39.9 kJ/mol and a low trap density but it is numerically demonstrated that saturated or diluted assumptions are not always verified, and a univocal determination of trapping parameters requires a broader range of charging conditions for permeation. The relationship between surface parameters, i.e. charging current, recombination current and surface concentrations, is also studied showing that trapping phenomena are stronger during the diluted steps and that recombination currents are much higher than the steady state obtained flux.

This study examines the use of hydrogen as an energy carrier for spreading renewable energy and mitigating environmental problems, and proposes a system for carrying clean water together with hydrogen. Practical simulations were carried out assuming the present conditions of Kazakhstan. The capital and most other large cities are located both far from clean water sources, and areas with plenty of sunshine. The proposed model consists of hydrogen generation by solar-powered electrolysis, transportation of hydrogen by railways and electric power generation using fuel cells in cities. The fuel cells also generate clean liquid water. This paper proposes a hydrogen transportation system by railway, where Ti-based hydrogen storage alloys fabricated with readily available metals in Kazakhstan are used. The railway is the most practical means of transportation compared to other methods in terms of utilities, economy, environment and time.