Transmission, Distribution & Storage
Complex Hydrides for Hydrogen Storage – New Perspectives
Apr 2014
Publication
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.
Simulation of the Inelastic Deformation of Porous Reservoirs Under Cyclic Loading Relevant for Underground Hydrogen Storage
Dec 2022
Publication
Subsurface geological formations can be utilized to safely store large-scale (TWh) renewable energy in the form of green gases such as hydrogen. Successful implementation of this technology involves estimating feasible storage sites including rigorous mechanical safety analyses. Geological formations are often highly heterogeneous and entail complex nonlinear inelastic rock deformation physics when utilized for cyclic energy storage. In this work we present a novel scalable computational framework to analyse the impact of nonlinear deformation of porous reservoirs under cyclic loading. The proposed methodology includes three diferent time-dependent nonlinear constitutive models to appropriately describe the behavior of sandstone shale rock and salt rock. These constitutive models are studied and benchmarked against both numerical and experimental results in the literature. An implicit time-integration scheme is developed to preserve the stability of the simulation. In order to ensure its scalability the numerical strategy adopts a multiscale fnite element formulation in which coarse scale systems with locally-computed basis functions are constructed and solved. Further the efect of heterogeneity on the results and estimation of deformation is analyzed. Lastly the Bergermeer test case—an active Dutch natural gas storage feld—is studied to investigate the infuence of inelastic deformation on the uplift caused by cyclic injection and production of gas. The present study shows acceptable subsidence predictions in this feld-scale test once the properties of the fnite element representative elementary volumes are tuned with the experimental data.
Liquid Hydrogen: A Review on Liquefaction, Storage, Transportation, and Safety
Sep 2021
Publication
Decarbonization plays an important role in future energy systems for reducing greenhouse gas emissions and establishing a zero-carbon society. Hydrogen is believed to be a promising secondary energy source (energy carrier) that can be converted stored and utilized efficiently leading to a broad range of possibilities for future applications. Moreover hydrogen and electricity are mutually converted creating high energy security and broad economic opportunities toward high energy resilience. Hydrogen can be stored in various forms including compressed gas liquid hydrogen hydrides adsorbed hydrogen and reformed fuels. Among these liquid hydrogen has advantages including high gravimetric and volumetric hydrogen densities and hydrogen purity. However liquid hydrogen is garnering increasing attention owing to the demand for long storage periods long transportation distances and economic performance. This paper reviews the characteristics of liquid hydrogen liquefaction technology storage and transportation methods and safety standards to handle liquid hydrogen. The main challenges in utilizing liquid hydrogen are its extremely low temperature and ortho- to para-hydrogen conversion. These two characteristics have led to the urgent development of hydrogen liquefaction storage and transportation. In addition safety standards for handling liquid hydrogen must be updated regularly especially to facilitate massive and large-scale hydrogen liquefaction storage and transportation.
Optimal Design of Stand-alone Solutions Based on RES + Hydrogen Storage Feeding Off-grid Communities
Apr 2021
Publication
Concerning off-grid areas diesel engines still dominate the scene of local electricity generation despite the related pollution concerns and high operating costs. There is thus a huge global potential in remote areas for exploiting local renewable energy sources (RES) in place of fossil generation. Energy storage systems become hence essential for off-grid communities to cope with the issue of RES intermittency allowing them to rely on locally harvested RES. In this work we analysed different typologies of off-grid renewable power systems involving batteries and hydrogen as means to store energy to find out which is the most cost-effective configuration in remote areas. Both Li-ion and lead-acid batteries were included in the analysis and both alkaline and PEM electrolysis technologies were considered for the production of hydrogen. Starting from single cell electrochemical models the performance curves of the electrolyser and fuel cell devices were derived for a more detailed techno-economic assessment. Lifetimes of batteries and H2-based components were also computed based on how the power-to-power (P2P) system operates along the reference year. The particle swarm optimization (PSO) algorithm was employed to find the component sizes that allow minimizing the levelized cost of energy (LCOE) while keeping the off-grid area energy autonomous. As a case study the Ginostra village on the island of Stromboli (North of Sicily Southern Italy) was analysed since it is well representative of small insular locations in the Mediterranean area. The renewable P2P solution (0.51 €/kWh for the cheapest configuration) was found to be economically preferable than the current existing power system relying on diesel generators (0.86 €/kWh). Hydrogen in particular can prevent the oversizing of both battery and PV systems thus reducing the final cost of electricity delivered by the P2P system. Moreover unlike diesel generators the RES-based configuration allows avoiding the production of local air pollutants and GHG emissions during its operation.
Seasonal Storage and Alternative Carriers: A Flexible Hydrogen Supply Chain Model
May 2017
Publication
A viable hydrogen infrastructure is one of the main challenges for fuel cells in mobile applications. Several studies have investigated the most cost-efficient hydrogen supply chain structure with a focus on hydrogen transportation. However supply chain models based on hydrogen produced by electrolysis require additional seasonal hydrogen storage capacity to close the gap between fluctuation in renewable generation from surplus electricity and fuelling station demand. To address this issue we developed a model that draws on and extends approaches in the literature with respect to long-term storage. Thus we analyse Liquid Organic Hydrogen Carriers (LOHC) and show their potential impact on future hydrogen mobility. We demonstrate that LOHC-based pathways are highly promising especially for smaller-scale hydrogen demand and if storage in salt caverns remains uncompetitive but emit more greenhouse gases (GHG) than other gaseous or hydrogen ones. Liquid hydrogen as a seasonal storage medium offers no advantage compared to LOHC or cavern storage since lower electricity prices for flexible operation cannot balance the investment costs of liquefaction plants. A well-to-wheel analysis indicates that all investigated pathways have less than 30% GHG-emissions compared to conventional fossil fuel pathways within a European framework.
Production Costs for Synthetic Methane in 2030 and 2050 of an Optimized Power-to-Gas Plant with Intermediate Hydrogen Storage
Aug 2019
Publication
The publication gives an overview of the production costs of synthetic methane in a Power-to-Gas process. The production costs depend in particularly on the electricity price and the full load hours of the plant sub-systems electrolysis and methanation. The full-load hours of electrolysis are given by the electricity supply concept. In order to increase the full-load hours of methanation the size of the intermediate hydrogen storage tank and the size of the methanation are optimised on the basis of the availability of hydrogen. The calculation of the production costs for synthetic methane are done with economics for 2030 and 2050 and the expenditures are calculated for one year of operation. The sources of volume of purchased electricity are the short-term market long-term contracts direct-coupled renewable energy sources or seasonal use of surpluses. Gas sales are either traded on the short-term market or guaranteed by long-term contracts. The calculations show that an intermediate storage tank for hydrogen adjustment of the methanation size and operating electrolysis and methanation separately increase the workload of the sub-system methanation. The gas production costs can be significantly reduced. With the future expected development of capital expenditures operational expenditure electricity prices gas costs and efficiencies an economic production of synthetic natural gas for the years 2030 especially for 2050 is feasible. The results show that Power-to-Gas is an option for long-term large-scale seasonal storage of renewable energy. Especially the cases with high operating hours for the sub-system methanation and low electricity prices show gas production costs below the expected market prices for synthetic gas and biogas.
Resilience-oriented Schedule of Microgrids with Hybrid Energy Storage System using Model Predictive Control
Nov 2021
Publication
Microgrids can be regarded as a promising solution by which to increase the resilience of power systems in an energy paradigm based on renewable generation. Their main advantage is their ability to work as islanded systems under power grid outage conditions. Microgrids are usually integrated into electrical markets whose schedules are carried out according to economic aspects while resilience criteria are ignored. This paper shows the development of a resilience-oriented optimization for microgrids with hybrid Energy Storage System (ESS) which is validated via numerical simulations. A hybrid ESS composed of hydrogen and batteries is therefore considered with the objective of improving the autonomy of the microgrid while achieving a rapid transition response. The control problem is formulated using Stochastic Model Predictive Control (SMPC) techniques in order to take into account possible transitions between grid-connected and islanded modes at all the sample instants of the schedule horizon (SH). The control problem is developed by considering a healthy operation of the hybrid ESS thus avoiding degradation issues. The plant is modeled using the Mixed Logic Dynamic (MLD) framework owing to the presence of logic and dynamic control variables.
Boron Hydrogen Compounds: Hydrogen Storage and Battery Applications
Dec 2021
Publication
About 25 years ago Bogdanovic and Schwickardi (B. Bogdanovic M. Schwickardi: J. Alloys Compd. 1–9 253 (1997) discovered the catalyzed release of hydrogen from NaAlH4 . This discovery stimulated a vast research effort on light hydrides as hydrogen storage materials in particular boron hydrogen compounds. Mg(BH4 )2 with a hydrogen content of 14.9 wt % has been extensively studied and recent results shed new light on intermediate species formed during dehydrogenation. The chemistry of B3H8 − which is an important intermediate between BH4 − and B12H12 2− is presented in detail. The discovery of high ionic conductivity in the high-temperature phases of LiBH4 and Na2B12H12 opened a new research direction. The high chemical and electrochemical stability of closo-hydroborates has stimulated new research for their applications in batteries. Very recently an all-solid-state 4 V Na battery prototype using a Na4 (CB11H12)2 (B12H12) solid electrolyte has been demonstrated. In this review we present the current knowledge of possible reaction pathways involved in the successive hydrogen release reactions from BH4 − to B12H12 2− and a discussion of relevant necessary properties for high-ionic-conduction materials.
The Effect of Heat Treatments on the Constituent Materials of a Nuclear Reactor Pressure Vessel in Hydrogen Environment
Jul 2016
Publication
A nuclear reactor pressure vessel (NRPV) wall is formed by two layer of different materials: an inner layer of stainless steel (cladding material) and an outer layer of low carbon steel (base material) which is highly susceptible to corrosion related phenomena. A reduction of the mechanical properties of both materials forming the wall would appear due to the action of the harsh environment causing hydrogen embrittlement (HE) related phenomena. As a result of the manufacturing process residual stresses and strains appear in the NRPV wall thereby influencing the main stage in HE: hydrogen diffusion. A common engineering practice for reducing such states is to apply a tempering heat treatment. In this paper a numerical analysis is carried out for revealing the influence of the heat treatment parameters (tempering temperature and tempering time) on the HE of a commonly used NRPV. To achieve this goal a numerical model of hydrogen diffusion assisted by stress and strain was used considering diverse residual stress-strain states after tempering. This way the obtained hydrogen accumulation during operation time of the NRPV provides insight into the better tempering conditions from the structural integrity point of view.
Techno-economic Assessment of Low-carbon Hydrogen Export from Western Canada to Eastern Canada, the USA, the Asia-Pacific, and Europe
Dec 2021
Publication
The use of low-carbon hydrogen is being considered to help decarbonize several jurisdictions around the world. There may be opportunities for energy-exporting countries to supply energy-importing countries with a secure source of low-carbon hydrogen. The study objective is to assess the delivered cost of gaseous hydrogen export from Canada (a fossil-resource rich country) to the Asia-Pacific Europe and inland destinations in North America. There is a data gap on the feasibility of inter-continental export of hydrogen from an energy-producing jurisdiction to energy-consuming jurisdictions. This study is aimed at addressing this gap and includes an assessment of opportunities across the Pacific Ocean and the Atlantic Ocean based on fundamental engineering-based models. Techno-economics were used to determine the delivered cost of hydrogen to these destinations. The modelling considers energy material and capacity-sizing requirements for a five-stage supply chain comprising hydrogen production with carbon capture and storage hydrogen pipeline transportation liquefaction shipping and regasification at the destinations. The results show that the delivered cost of hydrogen to inland destinations in North America is between CAD$4.81/kg and CAD$6.03/kg to the Asia-Pacific from CAD$6.65/kg to CAD$6.99/kg and at least CAD$8.14/kg for exports to Europe. Delivering hydrogen by blending in existing long-distance natural gas pipelines reduced the delivered cost to inland destinations by 17%. Exporting ammonia to the Asia-Pacific provides cost savings of 28% compared to shipping liquified hydrogen. The developed information may be helpful to policymakers in government and the industry in making informed decisions about international trade of low-carbon hydrogen in both energy-exporting and energy-importing jurisdictions globally.
New Liquid Chemical Hydrogen Storage Technology
Aug 2022
Publication
The liquid chemical hydrogen storage technology has great potentials for high-density hydrogen storage and transportation at ambient temperature and pressure. However its commercial applications highly rely on the high-performance heterogeneous dehydrogenation catalysts owing to the dehydrogenation difficulty of chemical hydrogen storage materials. In recent years the chemists and materials scientists found that the supported metal nanoparticles (MNPs) can exhibit high catalytic activity selectivity and stability for the dehydrogenation of chemical hydrogen storage materials which will clear the way for the commercial application of liquid chemical hydrogen storage technology. This review has summarized the recent important research progress in the MNP-catalyzed liquid chemical hydrogen storage technology including formic acid dehydrogenation hydrazine hydrate dehydrogenation and ammonia borane dehydrogenation discussed the urgent challenges in the key field and pointed out the future research trends.
Underground Hydrogen Storage: Application of Geochemical Modelling in a Case Study in the Molasse Basin, Upper Austria
Feb 2019
Publication
Hydrogen storage in depleted gas fields is a promising option for the large-scale storage of excess renewable energy. In the framework of the hydrogen storage assessment for the “Underground Sun Storage” project we conduct a multi-step geochemical modelling approach to study fluid–rock interactions by means of equilibrium and kinetic batch simulations. With the equilibrium approach we estimate the long-term consequences of hydrogen storage whereas kinetic models are used to investigate the interactions between hydrogen and the formation on the time scales of typical storage cycles. The kinetic approach suggests that reactions of hydrogen with minerals become only relevant over timescales much longer than the considered storage cycles. The final kinetic model considers both mineral reactions and hydrogen dissolution to be kinetically controlled. Interactions among hydrogen and aqueous-phase components seem to be dominant within the storage-relevant time span. Additionally sensitivity analyses of hydrogen dissolution kinetics which we consider to be the controlling parameter of the overall reaction system were performed. Reliable data on the kinetic rates of mineral dissolution and precipitation reactions specifically in the presence of hydrogen are scarce and often not representative of the studied conditions. These uncertainties in the kinetic rates for minerals such as pyrite and pyrrhotite were investigated and are discussed in the present work. The proposed geochemical workflow provides valuable insight into controlling mechanisms and risk evaluation of hydrogen storage projects and may serve as a guideline for future investigations.
Evaluating the Opportunity to Repurpose Gas Transmission Assets for Hydrogen Transportation
Sep 2021
Publication
The UK National Transmission System (NTS) is a key enabler to decarbonise the gas network in Great Britain (GB) in order to meet the UK government’s target of net-zero emissions by 2050. FutureGrid is National Grid’s research programme assessing the capability of the transmission system to transport hydrogen. Our goal is to accelerate the decarbonisation of power industry and heat by delivering a safe supply of energy to all customers both during and after the energy transition. FutureGrid will lead to a better understanding of what the technical parameters are around the ultimate role of the NTS in the energy system and how the transition can be managed. Under FutureGrid National Grid will construct a NTS hydrogen test facility at DNV’s Spadeadam testing and research site. NTS assets due to be decommissioned in early RIIO2 will be reconstructed to create a test network that can be used to answer some of the fundamental questions around safety and operation of a converted network. Flows of hydrogen/natural gas blends including 100% hydrogen will be tested for the first time in GB at transmission pressures. This system will connect to the existing H21 distribution network test facility at Spadeadam to prove a complete beach-to-meter network can be decarbonised to develop a comprehensive programme for the hydrogen transition. The project will provide a transmission facility which is a key enabler for more advanced hydrogen testing on industrial equipment such as hydrogen separation technology hydrogen compressors and/or purification of hydrogen for transport. Our paper will detail the current position and aims of the project.
Interfacial Fracture Strength Property of Micro-scale SiN/Cu Components
Jul 2016
Publication
The strength against fracture nucleation from an interface free-edge of silicon-nitride (SiN)/copper (Cu) micro-components is evaluated. A special technique that combines a nano-indenter specimen holder and an environmental transmission electron microscope (E-TEM) is employed. The critical load at the onset of fracture nucleation from a wedge-shaped free-edge (opening angle: 90°) is measured both in a vacuum and in a hydrogen (H2) environment and the critical stress distribution is evaluated by the finite element method (FEM). It is found that the fracture nucleation is dominated by the near-edge elastic singular stress field that extends about a few tens of nanometers from the edge. The fracture nucleation strength expressed in terms of the stress intensity factor (K) is found to be eminently reduced in a H2 environment.
Planning, Optimisation and Evaluation of Small Power-to-Gas-to-Power Systems: Case Study of a German Dairy
May 2022
Publication
In the course of the energy transition distributed hybrid energy systems such as the combination of photovoltaic (PV) and battery storages is increasingly being used for economic and ecological reasons. However renewable electricity generation is highly volatile and storage capacity is usually limited. Nowadays a new storage component is emerging: the power-to-gas-to-power (PtGtP) technology which is able to store electricity in the form of hydrogen even over longer periods of time. Although this technology is technically well understood and developed there are hardly any evaluations and feasibility studies of its widespread integration into current distributed energy systems under realistic legal and economic market conditions. In order to be able to give such an assessment we develop a methodology and model that optimises the sizing and operation of a PtGtP system as part of a hybrid energy system under current German market conditions. The evaluation is based on a multi-criteria approach optimising for both costs and CO2 emissions. For this purpose a brute-force-based optimal design approach is used to determine optimal system sizes combined with the energy system simulation tool oemof.solph. In order to gain further insights into this technology and its future prospects a sensitivity analysis is carried out. The methodology is used to examine the case study of a German dairy and shows that PtGtP is not yet profitable but promising.
Energy Management System for Hybrid PV/Wind/Battery/Fuel Cell in Microgrid-Based Hydrogen and Economical Hybrid Battery/Super Capacitor Energy Storage
Sep 2021
Publication
The present work addresses the modelling control and simulation of a microgrid integrated wind power system with Doubly Fed Induction Generator (DFIG) using a hybrid energy storage system. In order to improve the quality of the waveforms (voltages and currents) supplied to the grid instead of a two level-inverter the rotor of the DFIG is supplied using a three-level inverter. A new adaptive algorithm based on combined Direct Reactive Power Control (DRPC) and fuzzy logic controls techniques is applied to the proposed topology. In this work two topologies are proposed. In the first one the active power injected into the grid is smoothened by using an economical hybrid battery and supercapacitor energy storage system. However in the second one the excess wind energy is used to produce and store the hydrogen and then a solid oxide fuel cell system (SOFC) is utilized to regenerate electricity by using the stored hydrogen when there is not enough wind energy. To avoid overcharging deep discharging of batteries to mitigate fluctuations due to wind speed variations and to fulfil the requirement of the load profile a power management algorithm is implemented. This algorithm ensures smooth output power in the first topology and service continuity in the second. The modelling and simulation results are presented and analysed using Matlab/Simulin.
Performance Assessment of a Hybrid System with Hydrogen Storage and Fuel Cell for Cogeneration in Buildings
Jun 2020
Publication
The search for new fuels to supersede fossil fuels has been intensified these recent decades. Among these fuels hydrogen has attracted much interest due to its advantages mainly cleanliness and availability. It can be produced from various raw materials (e.g. water biomass) using many resources mainly water electrolysis and natural gas reforming. However water electrolysis combined with renewable energy sources is the cleanest way to produce hydrogen while reducing greenhouse gases. Besides hydrogen can be used by fuel cells for producing both electrical and thermal energy. The aim of this work was towards efficient integration of this system into energy efficient buildings. The system is comprised of a photovoltaic system hydrogen electrolyzer and proton exchange membrane fuel cell operating as a cogeneration system to provide the building with both electricity and thermal energy. The system’s modeling simulations and experimentations were first conducted over a short-run period to assess the system’s performance. Reported results show the models’ accuracy in analyzing the system’s performance. We then used the developed models for long-run testing of the hybrid system. Accordingly the system’s electrical efficiency was almost 32%. Its overall efficiency reached 64.5% when taking into account both produced electricity and thermal energy.
Thermodynamics and Kinetics of Hydriding and Dehydriding Reactions in Mg-based Hydrogen Storage Materials
Oct 2021
Publication
Mg-based materials are one of the most promising hydrogen storage candidates due to their high hydrogen storage capacity environmental benignity and high Clarke number characteristics. However the limited thermodynamics and kinetic properties pose major challenges for their engineering applications. Herein we review the recent progress in improving their thermodynamics and kinetics with an emphasis on the models and the influence of various parameters in the calculated models. Subsequently the impact of alloying composite and nano-crystallization on both thermodynamics and dynamics are discussed in detail. In particular the correlation between various modification strategies and the hydrogen capacity dehydrogenation enthalpy and temperature hydriding/dehydriding rates are summarized. In addition the mechanism of hydrogen storage processes of Mg-based materials is discussed from the aspect of classical kinetic theories and microscope hydrogen transferring behavior. This review concludes with an outlook on the remaining challenge issues and prospects.
Influence of Hydrogen Environment on Fatigue Fracture Morphology of X80 Pipeline Steel
Dec 2022
Publication
The rapid development of hydrogen energy requires the use of natural gas infrastructure for hydrogen transportation. It is very important to study hydrogen-added natural gas transportation technology which is a key way to rapidly develop coal-based gas and renewable energy. This study aims to study the influence of X80 pipeline steel's fatigue performance in hydrogen environment and perform fatigue tests on notched round rod specimens under different hydrogen concentration. The experimental results show that hydrogen seriously affects the fatigue life of pipeline steel. After reaching a certain hydrogen concentration as the hydrogen concentration continues to increase the fatigue life decreases gradually. Combined with SEM analysis of fracture morphology the decrease in the size and density of the dimples reduces the displacement amplitude while the increase in the planar area increases the displacement during fatigue fracture due to accelerated crack propagation. From this study we can know the influence of hydrogen concentration on the fracture morphology of pipeline steel which provides an understanding of the effect of hydrogen on fatigue fracture morphology and a broader safety analysis.
Analysis of Hydrogen in Inorganic Materials and Coatings: A Critical Review
Jun 2021
Publication
The currently used bulk analysis and depth profiling methods for hydrogen in inorganic materials and inorganic coatings are reviewed. Bulk analysis of hydrogen is based on fusion of macroscopic samples in an inert gas and the detection of the thereby released gaseous H2 using inert gas fusion (IGF) and thermal desorption spectroscopy (TDS). They offer excellent accuracy and sensitivity. Depth profiling methods involve glow discharge optical emission spectroscopy and mass spectrometry (GDOES and GDMS) laser-induced breakdown spectroscopy (LIBS) secondary ion mass spectrometry (SIMS) nuclear reaction analysis (NRA) and elastic recoil detection analysis (ERDA). The principles of all these methods are explained in terms of the methodology calibration procedures analytical performance and major application areas. The synergies and the complementarity of various methods of hydrogen analysis are described. The existing literature about these methods is critically evaluated and major papers concerning each method are listed.
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