Transmission, Distribution & Storage
Improved Overall Hydrogen Storage Properties of a CsH and KH Co-doped Mg(NH2)2/2LiH System by Forming Mixed Amides of Li–K and Cs–Mg
Jun 2017
Publication
A CsH and KH co-doped Mg(NH2)2/2LiH composite was prepared with a composition of Mg(NH2)2/2LiH–(0.08 − x)CsH–xKH and the hydrogen storage characteristics was systematically investigated. The results showed that the presence of KH further improved the reaction thermodynamics and kinetics of hydrogen storage in a CsH-containing Mg(NH2)2/2LiH system. A sample with 0.04 mol CsH and 0.04 mol KH had optimal hydrogen storage performance; its dehydrogenation could proceed at 130 °C and hydrogenation at 120 °C with 4.89 wt% of hydrogen storage capacity. At 130 °C a 25-fold increase in the dehydrogenation rate was achieved for the CsH and KH co-doped sample. More importantly the CsH and KH co-doped sample also had good cycling stability because more than 97% of the hydrogen storage capacity (4.34 wt%) remained for theMg(NH2)2/2LiH–0.04CsH–0.04KH sample after 30 cycles. A structural characterization revealed that added CsH and KH participated in the dehydrogenation and hydrogenation reactions by reversibly forming mixed amides of Li–K and Cs–Mg which caused the improved hydrogen storage thermodynamics and kinetics.
Synthesis and Characterization of Carbon-Based Composites for Hydrogen Storage Application
Dec 2021
Publication
Recent development shows that carbon-based composites are proving to be the most promising materials in hydrogen energy production storage and conversion applications. In this study composites of the copper-based metal-organic framework with different ratios of graphite oxide have been prepared for hydrogen storage application. The developed materials are characterized by X-ray diffraction (XRD) gravimetric thermal analysis (TGA) scanning electron microscopy (SEM) and BET. The newly developed composites have an improved crystalline structure and an increased surface area. The results of the experiment showed that the composite material MOF/GO 20% can store 6.12% of hydrogen at −40 ◦C.
Scenarios to Decarbonize Austria’s Energy Consumption and the Role of Underground Hydrogen Storage
May 2022
Publication
The European Union is aiming at reaching greenhouse gas (GHG) emission neutrality in 2050. Austria’s current greenhouse gas emissions are 80 million t/year. Renewable Energy (REN) contributes 32% to Austria’s total energy consumption. To decarbonize energy consumption a substantial increase in energy generation from renewable energy is required. This increase will add to the seasonality of energy supply and amplifies the seasonality in energy demand. In this paper the seasonality of energy supply and demand in a Net-Zero Scenario are analyzed for Austria and requirements for hydrogen storage derived. We looked into the potential usage of hydrogen in Austria and the economics of hydrogen generation and technology and market developments to assess the Levelized Cost of Hydrogen (LCOH). Then we cover the energy consumption in Austria followed by the REN potential. The results show that incremental potential of up to 140 TWh for hydropower photovoltaic (PV) and wind exists in Austria. Hydropower generation and PV is higher in summer- than in wintertime while wind energy leads to higher energy generation in wintertime. The largest incremental potential is PV with agrivoltaic systems significantly increasing the area amenable for PV compared with PV usage only. Battery Electric Vehicles (BEV) and Fuel Cell Vehicles (FCV) use energy more efficiently than Internal Combustion Engine (ICE) cars; however the use of hydrogen for electricity generation significantly decreases the efficiency due to electricity–hydrogen– electricity conversion. The increase in REN use and the higher demand for energy in Austria in wintertime require seasonal storage of energy. We developed three scenarios Externally Dependent Scenario (EDS) Balanced Energy Scenario (BES) or Self-Sustained Scenario (SSS) for Austria. The EDS scenario assumes significant REN import to Austria whereas the SSS scenario relies on REN generation within Austria. The required hydrogen storage would be 10.82 bn m3 for EDS 13.34 bn m3 for BES and 18.69 bn m3 for SSS. Gas and oil production in Austria and the presence of aquifers indicates that sufficient storage capacity might be available. Significant technology development is required to be able to implement hydrogen as an energy carrier and to balance seasonal energy demand and supply.
Empowering Hydrogen Storage Properties of Haeckelite Monolayers via Metal Atom Functionalization
Mar 2021
Publication
Using hydrogen as an energy carrier requires new technological solutions for its onboard storage. The exploration of two-dimensional (2D) materials for hydrogen storage technologies has been motivated by their open structures which facilitates fast hydrogen kinetics. Herein the hydrogen storage properties of lightweight metal functionalized r57 haeckelite sheets are studied using density functional theory (DFT) calculations. H2 molecules are adsorbed on pristine r57 via physisorption. The hydrogen storage capacity of r57 is improved by decorating it with alkali and alkaline-earth metals. In addition the in-plane substitution of r57 carbons with boron atoms (B@r57) both prevents the clustering of metals on the surface of 2D material and increases the hydrogen storage capacity by improving the adsorption thermodynamics of hydrogen molecules. Among the studied compounds B@r57-Li4 with its 10.0 wt% H2 content and 0.16 eV/H2 hydrogen binding energy is a promising candidate for hydrogen storage applications. A further investigation as based on the calculated electron localization functions atomic charges and electronic density of states confirm the electrostatic nature of interactions between the H2 molecules and the protruding metal atoms on 2D haeckelite sheets. All in all this work contributes to a better understanding of pure carbon and B-doped haeckelites for hydrogen storage.
Mechanical Properties and Hydrogen Embrittlement of Laser-Surface Melted AISI 430 Ferritic Stainless Steel
Feb 2020
Publication
Hydrogen was doped in austenitic stainless steel (ASS) 316L tensile samples produced by the laser-powder bed fusion (L-PBF) technique. For this aim an electrochemical method was conducted under a high current density of 100 mA/cm2 for three days to examine its sustainability under extreme hydrogen environments at ambient temperatures. The chemical composition of the starting powders contained a high amount of Ni approximately 12.9 wt.% as a strong austenite stabilizer. The tensile tests disclosed that hydrogen charging caused a minor reduction in the elongation to failure (approximately 3.5% on average) and ultimate tensile strength (UTS; approximately 2.1% on average) of the samples using a low strain rate of 1.2 × 10−4 s−1. It was also found that an increase in the strain rate from 1.2 × 10−4 s−1 to 4.8 × 10−4 s−1 led to a reduction of approximately 3.6% on average for the elongation to failure and 1.7% on average for UTS in the pre-charged samples. No trace of martensite was detected in the X-ray diffraction (XRD) analysis of the fractured samples thanks to the high Ni content which caused a minor reduction in UTS × uniform elongation (UE) (GPa%) after the H charging. Considerable surface tearing was observed for the pre-charged sample after the tensile deformation. Additionally some cracks were observed to be independent of the melt pool boundaries indicating that such boundaries cannot necessarily act as a suitable area for the crack propagation.
Potential Liquid-Organic Hydrogen Carrier (LOHC) Systems: A Review on Recent Progress
Nov 2020
Publication
The depletion of fossil fuels and rising global warming challenges encourage to find safe and viable energy storage and delivery technologies. Hydrogen is a clean efficient energy carrier in various mobile fuel-cell applications and owned no adverse effects on the environment and human health. However hydrogen storage is considered a bottleneck problem for the progress of the hydrogen economy. Liquid-organic hydrogen carriers (LOHCs) are organic substances in liquid or semi-solid states that store hydrogen by catalytic hydrogenation and dehydrogenation processes over multiple cycles and may support a future hydrogen economy. Remarkably hydrogen storage in LOHC systems has attracted dramatically more attention than conventional storage systems such as high-pressure compression liquefaction and absorption/adsorption techniques. Potential LOHC media must provide fully reversible hydrogen storage via catalytic processes thermal stability low melting points favorable hydrogenation thermodynamics and kinetics large-scale availability and compatibility with current fuel energy infrastructure to practically employ these molecules in various applications. In this review we present various considerable aspects for the development of ideal LOHC systems. We highlight the recent progress of LOHC candidates and their catalytic approach as well as briefly discuss the theoretical insights for understanding the reaction mechanism.
Particle Size and Crystal Phase Effects in Fischer-Tropsch Catalysts
Aug 2017
Publication
Fischer-Tropsch synthesis (FTS) is an increasingly important approach for producing liquid fuels and chemicals via syngas—that is synthesis gas a mixture of carbon monoxide and hydrogen—generated from coal natural gas or biomass. In FTS dispersed transition metal nanoparticles are used to catalyze the reactions underlying the formation of carbon-carbon bonds. Catalytic activity and selectivity are strongly correlated with the electronic and geometric structure of the nanoparticles which depend on the particle size morphology and crystallographic phase of the nanoparticles. In this article we review recent works dealing with the aspects of bulk and surface sensitivity of the FTS reaction. Understanding the different catalytic behavior in more detail as a function of these parameters may guide the design of more active selective and stable FTS catalysts.
Effective Thermal Conductivity of Insulation Materials for Cryogenic LH2 Storage Tanks: A Review
Nov 2022
Publication
An accurate estimation of the effective thermal conductivity of various insulation materials is essential in the evaluation of heat leak and boil-off rate from liquid hydrogen storage tanks. In this work we review the existing experimental data and various proposed correlations for predicting the effective conductivity of insulation systems consisting of powders foams fibrous materials and multilayer systems. We also propose a first principles-based correlation that may be used to estimate the dependence of the effective conductivity as a function of temperature interstitial gas composition pressure and structural properties of the material. We validate the proposed correlation using available experimental data for some common insulation materials. Further improvements and testing of the proposed correlation using laboratory scale data obtained using potential LH2 tank insulation materials are also discussed.
AI Agents Envisioning the Future: Forecast-based Operation of Renewable Energy Storage Systems Using Hydrogen with Deep Reinforcement Learning
Feb 2022
Publication
Hydrogen-based energy storage has the potential to compensate for the volatility of renewable power generation in energy systems with a high renewable penetration. The operation of these storage facilities can be optimized using automated energy management systems. This work presents a Reinforcement Learning-based energy management approach in the context of CO2-neutral hydrogen production and storage for an industrial combined heat and power application. The economic performance of the presented approach is compared to a rule-based energy management strategy as a lower benchmark and a Dynamic Programming-based unit commitment as an upper benchmark. The comparative analysis highlights both the potential benefits and drawbacks of the implemented Reinforcement Learning approach. The simulation results indicate a promising potential of Reinforcement Learning-based algorithms for hydrogen production planning outperforming the lower benchmark. Furthermore a novel approach in the scientific literature demonstrates that including energy and price forecasts in the Reinforcement Learning observation space significantly improves optimization results and allows the algorithm to take variable prices into account. An unresolved challenge however is balancing multiple conflicting objectives in a setting with few degrees of freedom. As a result no parameterization of the reward function could be found that fully satisfied all predefined targets highlighting one of the major challenges for Reinforcement Learning -based energy management algorithms to overcome.
Heat Transfer Analysis of High Pressure Hydrogen Tank Fillings
Jun 2022
Publication
Fast fillings of hydrogen vehicles require proper control of the temperature to ensure the integrity of the storage tanks. This study presents an analysis of heat transfer during filling of a hydrogen tank. A conjugate heat transfer based on energy balance is introduced. The numerical model is validated against fast filling experiments of hydrogen in a Type IV tank by comparing the gas temperature evolution. The impact of filling parameters such as initial temperature inlet nozzle diameter and filling time is then assessed. For the considered Type IV tank the results show that both a higher and lower tank shell thermal conductivity results in lower inner wall peak temperatures. The presented model provides an analytical description of the temperature evolution in the gas and in the tank shell and is thus a useful tool to explore a broad range of parameters e.g. to determine new hydrogen filling protocols.
Impact of Local Emergency Demand Response Programs on the Operation of Electricity and Gas Systems
Mar 2022
Publication
With increasing attention to climate change the penetration level of renewable energy sources (RES) in the electricity network is increasing. Due to the intermittency of RES gas‐fired power plants could play a significant role in backing up the RES in order to maintain the supply– demand balance. As a result the interaction between gas and power networks are significantly in‐ creasing. On the other hand due to the increase in peak demand (e.g. electrification of heat) net‐ work operators are willing to execute demand response programs (DRPs) to improve congestion management and reduce costs. In this context modeling and optimal implementation of DRPs in proportion to the demand is one of the main issues for gas and power network operators. In this paper an emergency demand response program (EDRP) is implemented locally to reduce the con‐ gestion of transmission lines and gas pipelines more efficiently. Additionally the effects of optimal implementation of local emergency demand response program (LEDRP) in gas and power networks using linear and non‐linear economic models (power exponential and logarithmic) for EDRP in terms of cost and line congestion and risk of unserved demand are investigated. The most reliable demand response model is the approach that has the least difference between the estimated demand and the actual demand. Furthermore the role of the LEDRP in the case of hydrogen injection instead of natural gas in the gas infrastructure is investigated. The optimal incentives for each bus or node are determined based on the power transfer distribution factor gas transfer distribution factor available electricity or gas transmission capability and combination of unit commitment with the LEDRP in the integrated operation of these networks. According to the results implementing the LEDRP in gas and power networks reduces the total operation cost up to 11% and could facilitate hydrogen injection to the network. The proposed hybrid model is implemented on a 24‐bus IEEE electricity network and a 15‐bus gas network to quantify the role and value of different LEDRP models.
Two-stage Model Predictive Control for a Hydrogen-based Storage System Paired to a Wind Farm Towards Green Hydrogen Production for Fuel Cell Electric Vehicles
Jul 2022
Publication
This study proposes a multi-level model predictive control (MPC) for a grid-connected wind farm paired to a hydrogen-based storage system (HESS) to produce hydrogen as a fuel for commercial road vehicles while meeting electric and contractual loads at the same time. In particular the integrated system (wind farm + HESS) should comply with the “fuel production” use case as per the IEA-HIA report where the hydrogen production for fuel cell electric vehicles (FCEVs) has the highest unconditional priority among all the objectives. Based on models adopting mixed-integer constraints and dynamics the problem of external hydrogen consumer requests optimal load demand tracking and electricity market participation is solved at different timescales to achieve a long-term plan based on forecasts that then are adjusted at real-time. The developed controller will be deployed onto the management platform of the HESS which is paired to a wind farm established in North Norway within the EU funded project HAEOLUS. Numerical analysis shows that the proposed controller efficiently manages the integrated system and commits the equipment so as to comply with the requirements of the addressed scenario. The operating costs of the devices are reduced by 5% which corresponds to roughly 300 commutations saved per year for devices.
A Study on the Prediction of the Temperature and Mass of Hydrogen Gas inside a Tank during Fast Filling Process
Dec 2020
Publication
The hydrogen compression cycle system recycles hydrogen compressed by a compressor at high pressure and stores it in a high-pressure container. Thermal stress is generated due to increase in the pressure and temperature of hydrogen in the hydrogen storage tank during the fast filing process. For the sake of safety it is of great practical significance to predict and control the temperature change in the tank. The hydrogen charging process in the storage tank of the hydrogen charging station was studied by experimentation and simulation. In this paper a Computational Fluid Dynamics (CFD) model for non-adiabatic real filling of a 50 MPa hydrogen cylinder was presented. In addition a shear stress transport (k-ω) model and real gas model were used in order to account for thermo-fluid dynamics during the filling of hydrogen storage tanks (50 MPa 343 L). Compared to the simulation results with the experimental data carried out under the same conditions the temperatures calculated from the simulated non-adiabatic condition results were lower (by 5.3%) than those from the theoretical adiabatic condition calculation. The theoretical calculation was based on the experimentally measured pressure value. The calculated simulation mass was 8.23% higher than the theoretical result. The results of this study will be very useful in future hydrogen energy research and hydrogen charging station developments.
Recent Developments in State-of-the-art Hydrogen Energy Technologies – Review of Hydrogen Storage Materials
Jan 2023
Publication
Hydrogen energy has been assessed as a clean and renewable energy source for future energy demand. For harnessing hydrogen energy to its fullest potential storage is a key parameter. It is well known that important hydrogen storage characteristics are operating pressure-temperature of hydrogen hydrogen storage capacity hydrogen absorption-desorption kinetics and heat transfer in the hydride bed. Each application needs specific properties. Every class of hydrogen storage materials has a different set of hydrogenation characteristics. Hence it is required to understand the properties of all hydrogen storage materials. The present review is focused on the state-of– the–art hydrogen storage materials including metal hydrides magnesium-based materials complex hydride systems carbonaceous materials metal organic frameworks perovskites and materials and processes based on artificial intelligence. In each category of materials‘ discovery hydrogen storage mechanism and reaction crystal structure and recent progress have been discussed in detail. Together with the fundamental synthesis process latest techniques of material tailoring like nanostructuring nanoconfinement catalyzing alloying and functionalization have also been discussed. Hydrogen energy research has a promising potential to replace fossil fuels from energy uses especially from automobile sector. In this context efforts initiated worldwide for clean hydrogen production and its use via fuel cell in vehicles is much awaiting steps towards sustainable energy demand.
Assessment of Hydrogen Based Long Term Electrical Storage in Residential Energy Systems
Oct 2022
Publication
Among the numerous envisioned applications for hydrogen in the decarbonization of the energy system seasonal energy storage is usually regarded as one of the most likely options. Although long-term energy storage is usually considered at grid-scale level given the increasing diffusion of distributed energy systems and the expected cost reduction in hydrogen related components some companies are starting to offer residential systems with PV modules and batteries that rely on hydrogen for seasonal storage of electrical energy. Such hydrogen storage systems are generally composed by water electrolysers hydrogen storage vessels and fuel cells.<br/>The aim of this work is to investigate such systems and their possible applications for different geographical conditions in Italy. On-grid and off-grid systems are considered and compared to systems without hydrogen in terms of self-consumption ratio size of components and economic investment. Each different option has been assessed from a techno-economic point of view via MESS (Multi Energy Systems Simulator) an analytical programming tool for the analysis of local energy systems.<br/>Results have identified the optimal sizing of the system's components and have shown how such systems are not in general economically competitive for a single dwelling although they can in some cases ensure energy independence.
Recent Development in Nanoconfined Hydrides for Energy Storage
Jun 2022
Publication
Hydrogen is the ultimate vector for a carbon-free sustainable green-energy. While being the most promising candidate to serve this purpose hydrogen inherits a series of characteristics making it particularly difficult to handle store transport and use in a safe manner. The researchers’ attention has thus shifted to storing hydrogen in its more manageable forms: the light metal hydrides and related derivatives (ammonia-borane tetrahydridoborates/borohydrides tetrahydridoaluminates/alanates or reactive hydride composites). Even then the thermodynamic and kinetic behavior faces either too high energy barriers or sluggish kinetics (or both) and an efficient tool to overcome these issues is through nanoconfinement. Nanoconfined energy storage materials are the current state-of-the-art approach regarding hydrogen storage field and the current review aims to summarize the most recent progress in this intriguing field. The latest reviews concerning H2 production and storage are discussed and the shift from bulk to nanomaterials is described in the context of physical and chemical aspects of nanoconfinement effects in the obtained nanocomposites. The types of hosts used for hydrogen materials are divided in classes of substances the mean of hydride inclusion in said hosts and the classes of hydrogen storage materials are presented with their most recent trends and future prospects.
Selection of Underground Hydrogen Storage Risk Assessment Techniques
Dec 2021
Publication
The article proposes the use of the analytic hierarchy process (AHP) method to select a risk assessment technique associated with underground hydrogen storage. The initial choosing and ranking of risk assessment techniques can be considered as a multi-criteria decision problem. The usage of a decision model based on six criteria is proposed. A ranking of methods for estimating the risks associated with underground hydrogen storage is presented. The obtained results show that the application of the AHP-based approach may be a useful tool for selecting the UHS risk assessment technique. The proposed method makes it possible to make an objective decision of the most satisfactory approach from the point of view of all the adopted decision criteria regarding the selection of the best risk assessment technique.
Metallic Materials for Hydrogen Storage—A Brief Overview
Nov 2022
Publication
The research and development of materials suitable for hydrogen storage has received a great deal of attention worldwide. Due to the safety risks involved in the conventional storage of hydrogen in its gaseous or liquid phase in containers and tanks development has focused on solid-phase hydrogen storage including metals. Light metal alloys and high-entropy alloys which have a high potential for hydrogen absorption/desorption at near-standard ambient conditions are receiving interest. For the development of these alloys due to the complexity of their compositions a computational approach using CALPHAD (Calculation of Phases Diagrams) and machine learning (ML) methods that exploit thermodynamic databases of already-known and experimentally verified systems are being increasingly applied. In order to increase the absorption capacity or to decrease the desorption temperature and to stabilize the phase composition specific material preparation methods (HEBM—high-energy milling HPT—high-pressure torsion) referred to as activation must be applied for some alloys.
Hydrogen Permeation Behavior of QP1180 High Strength Steel in Simulated Coastal Atmosphere
Mar 2022
Publication
The hydrogen permeation behavior of QP1180 high strength steel for automobile was studied in simulate coastal atmosphere environment by using Devanathan-Stachurski dual electrolytic cell the cyclic corrosion test (CCT) thermal desorption spectrometry (TDS) and electrochemical measurement methods. The current density of hydrogen permeation generally increases with reducing the relative humidity from 95% to 50% and periodically changes in the CCT process. These mainly result from the evolution of corrosion and rust layer on the specimen surface with the atmospheric humidity and intermittent salt spraying. The contents of diffusible hydrogen and non-diffusible hydrogen in the steel enlarge slightly in the CCT process. The plastic deformation about 11.3% results in much higher diffusible hydrogen content in steel but noticeably reduces the hydrogen permeation current and almost has no influence on the non-diffusible hydrogen content. The combination of double electrolytic cell and standard cyclic corrosion test can effectively characterize the hydrogen permeation of high strength steel in atmospheric service environments.
Recent Progress on Hydrogen Storage and Production Using Chemical Hydrogen Carriers
Jul 2022
Publication
Depleting fossil fuel resources and anthropogenic climate changes are the reasons for the intensive development of new sustainable technologies based on renewable energy sources. One of the most promising strategies is the utilization of hydrogen as an energy vector. However the limiting issue for large-scale commercialization of hydrogen technologies is a safe efficient and economical method of gas storage. In industrial practice hydrogen compression and liquefaction are currently applied; however due to the required high pressure (30–70 MPa) and low temperature (−253 ◦C) both these methods are intensively energy consuming. Chemical hydrogen storage is a promising alternative as it offers safe storage of hydrogen-rich compounds under ambient conditions. Although many compounds serving as hydrogen carriers are considered some of them do not have realistic perspectives for large-scale commercialization. In this review the three most technologically advanced hydrogen carriers—dimethyl ether methanol and dibenzyltoluene—are discussed and compared. Their potential for industrial application in relation to the energy storage transport and mobility sectors is analyzed taking into account technological and environmental aspects.
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