Transmission, Distribution & Storage
Everything About Hydrogen Podcast: Envisioning the Hydrogen Revolution
May 2021
Publication
For our 40th episode of the Everything About Hydrogen podcast the gang are joined by hydrogen luminary Marco Alverà the CEO of Snam. Founded in 1941 and listed on the Italian stock exchange since 2001 Snam is a leader in the European gas market and operator of over 41000km of transport networks. Hailed as a visionary who has led the pivot of the world’s 2nd largest gas distribution company towards a clean gas trajectory Marco is widely recognized as a thought leader and a key figure driving the transition towards hydrogen. On the show the team discuss why Marco decided to lead Snam's pivot towards hydrogen what he sees as the role of hydrogen in the energy transition and how blue hydrogen can sit alongside green hydrogen as part of the solution to a decarbonized gas network.
The podcast can be found on their website
The podcast can be found on their website
Aspects of Hydrogen and Biomethane Introduction in Natural Gas Infrastructure and Equipment
Aug 2021
Publication
The injection of green hydrogen and biomethane is currently seen as the next step towards the decarbonization of the gas sector in several countries. However the introduction of these gases in existent infrastructure has energetic material and operational implications that should be carefully looked at. With regard to a fully blown green gas grid transport and distribution will require adaptations. Furthermore the adequate performance of end-use equipment connected to the grid must be accounted for. In this paper a technical analysis of the energetic material and operational aspects of hydrogen and biomethane introduction in natural gas infrastructure is performed. Impacts on gas transmission and distribution are evaluated and an interchangeability analysis supported by one-dimensional Cantera simulations is conducted. Existing gas infrastructure seems to be generally fit for the introduction of hydrogen and biomethane. Hydrogen content up to 20% by volume appears to be possible to accommodate in current infrastructure with only minor technical modifications. However at the Distribution System Operator (DSO) level the introduction of gas quality tracking systems will be required due to the distributed injection nature of hydrogen and biomethane. The different tolerances for hydrogen blending of consumers depending on end-use equipment may be critical during the transition period to a 100% green gas grid as there is a risk of pushing consumers off the grid.
Mapping Geological Hydrogen Storage Capacity and Regional Heating Demands: An Applied UK Case Study
Feb 2021
Publication
Hydrogen is considered as a low-carbon substitute for natural gas in the otherwise difficult to decarbonise domestic heating sector. This study presents for the first time a globally applicable source to sink methodology and analysis that matches geological storage capacity with energy demand. As a case study it is applied to the domestic heating system in the UK with a focus on maintaining the existing gas distribution network. To balance the significant annual cyclicity in energy demand for heating hydrogen could be stored in gas fields offshore and transported via offshore pipelines to the existing gas terminals into the gas network. The hydrogen energy storage demand in the UK is estimated to be ~77.9 terawatt-hour (TWh) which is approximately 25 % of the total energy from natural gas used for domestic heating. The total estimated storage capacity of the gas fields included in this study is 2661.9 TWh. The study reveals that only a few offshore gas fields are required to store enough energy as hydrogen to balance the entire seasonal demand for UK domestic heating. It also demonstrates that as so few fields are required hydrogen storage will not compete for the subsurface space required for other low-carbon subsurface applications such as carbon storage or compressed air energy storage.
Optimization of Operating Hydrogen Storage System for Coal–Wind–Solar Power Generation
Jul 2022
Publication
To address the severity of the wind and light abandonment problem and the economics of hydrogen energy production and operation this paper explores the problem of multi-cycle resource allocation optimization of hydrogen storage systems for coal–wind–solar power generation. In view of the seriousness of the problem of abandoning wind and photovoltaic power and the economy of hydrogen production and operation the node selection and scale setting issues for hydrogen production and storage as well as decision-making problems such as the capacity of new transmission lines and new pipelines and route planning are studied. This research takes the satisfaction of energy supply as the basic constraint and constructs a multi-cycle resource allocation optimization model for an integrated energy system aiming to achieve the maximum benefit of the whole system. Using data from Inner Mongolia where wind abandonment and power limitation are severe and Beijing and Shanxi provinces where hydrogen demand is high this paper analyzes the benefits of the hydrogen storage system for coal–wind–solar power generation and explores the impact of national subsidy policies and technological advances on system economics.
Current Research Progress in Magnesium Borohydride for Hydrogen Storage (A review)
Nov 2021
Publication
Hydrogen storage in solid-state materials is believed to be a most promising hydrogen-storage technology for high efficiency low risk and low cost. Mg(BH4)2 is regarded as one of most potential materials in hydrogen storage areas in view of its high hydrogen capacities (14.9 wt% and 145–147 kg cm3 ). However the drawbacks of Mg(BH4)2 including high desorption temperatures (about 250 C–580 C) sluggish kinetics and poor reversibility make it difficult to be used for onboard hydrogen storage of fuel cell vehicles. A lot of researches on improving the dehydrogenation reaction thermodynamics and kinetics have been done mainly including: additives or catalysts doping nanoconfining Mg(BH4)2 in nanoporous hosts forming reactive hydrides systems multi-cation/anion composites or other derivatives of Mg(BH4)2. Some favorable results have been obtained. This review provides an overview of current research progress in magnesium borohydride including: synthesis methods crystal structures decomposition behaviors as well as emphasized performance improvements for hydrogen storage.
Geological Hydrogen Storage: Geochemical Reactivity of Hydrogen with Sandstone Reservoirs
Jun 2022
Publication
The geological storage of hydrogen is necessary to enable the successful transition to a hydrogen economy and achieve net-zero emissions targets. Comprehensive investigations must be undertaken for each storage site to ensure their long-term suitability and functionality. As such the systematic infrastructure and potential risks of large-scale hydrogen storage must be established. Herein we conducted over 250 batch reaction experiments with different types of reservoir sandstones under conditions representative of the subsurface reflecting expected time scales for geological hydrogen storage to investigate potential reactions involving hydrogen. Each hydrogen experiment was paired with a hydrogen-free control under otherwise identical conditions to ensure that any observed reactions were due to the presence of hydrogen. The results conclusively reveal that there is no risk of hydrogen loss or reservoir integrity degradation due to abiotic geochemical reactions in sandstone reservoirs.
Carbon Capture from Biogas by Deep Eutectic Solvents A COSMO Study to Evaluate the Effect of Impurities on Solubility and Selectivity
Jun 2021
Publication
Deep eutectic solvents (DES) are compounds of a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA) that contain a depressed melting point compared to their individual constituents. DES have been studied for their use as carbon capture media and biogas upgrading. However contaminants’ presence in biogas might affect the carbon capture by DES. In this study conductor-like screening model for real solvents (COSMO-RS) was used to determine the effect of temperature pressure and selective contaminants on five DES’ namely choline chloride-urea choline chloride-ethylene glycol tetra butyl ammonium chloride-ethylene glycol tetra butyl ammonium bromide-decanoic acid and tetra octyl ammonium chloride-decanoic acid. Impurities studied in this paper are hydrogen sulfide ammonia water nitrogen octamethyltrisiloxane and decamethylcyclopentasiloxane. At infinite dilution CO2 solubility dependence upon temperature in each DES was examined by means of Henry’s Law constants. Next the systems were modeled from infinite dilution to equilibrium using the modified Raoults’ Law where CO2 solubility dependence upon pressure was examined. Finally solubility of CO2 and CH4 in the various DES were explored with the presence of varying mole percent of selective contaminants. Among the parameters studied it was found that the HBD of the solvent is the most determinant factor for the effectiveness of CO2 solubility. Other factors affecting the solubility are alkyl chain length of the HBA the associated halogen and the resulting polarity of the DES. It was also found that choline chloride-urea is the most selective to CO2 but has the lowest CO2 solubility and is the most polar among other solvents. On the other hand tetraoctylammonium chloride-decanoic acid is the least selective has the highest maximum CO2 solubility is the least polar and is the least affected by its environment.
Neutron Scattering and Hydrogen Storage
Nov 2009
Publication
Hydrogen has been identified as a fuel of choice for providing clean energy for transport and other applications across the world and the development of materials to store hydrogen efficiently and safely is crucial to this endeavour. Hydrogen has the largest scattering interaction with neutrons of all the elements in the periodic table making neutron scattering ideal for studying hydrogen storage materials. Simultaneous characterisation of the structure and dynamics of these materials during hydrogen uptake is straightforward using neutron scattering techniques. These studies will help us to understand the fundamental properties of hydrogen storage in realistic conditions and hence design new hydrogen storage materials.
Towards Electrochemical Hydrogen Storage in Liquid Organic Hydrogen Carriers via Proton-coupled Electron Transfers
Jun 2022
Publication
Green hydrogen is identified as one of the prime clean energy carriers due to its high energy density and a zero emission of CO2. A possible solution for the transport of H2 in a safe and low-cost way is in the form of liquid organic hydrogen carriers (LOHCs). As an alternative to loading LOHC with H2 via a two-step procedure involving preliminary electrolytic production of H2 and subsequent chemical hydrogenation of the LOHC we explore here the possibility of electrochemical hydrogen storage (EHS) via conversion of proton of a proton donor into a hydrogen atom involved in covalent bonds with the LOHC (R) via a proton-coupled electron transfer (PCET) reaction: . 2 + +2 ― + ox↔ 0 2red We chose 9-fluorenone/fluorenol (Fnone/Fnol) conversion as such a model PCET reaction. The electrochemical activation of Fnone via two sequential electron transfers was monitored with in-situ and operando spectroscopies in absence and in presence of different alcohols as proton donors of different reactivity which enabled us to both quantify and get the mechanistic insight on PCET. The possibility of hydrogen extraction from the loaded carrier molecule was illustrated by chemical activation.
A Quantitative Assessment of the Hydrogen Storage Capacity of the UK Continental Shelf
Nov 2020
Publication
Increased penetration of renewable energy sources and decarbonisation of the UK's gas supply will require large-scale energy storage. Using hydrogen as an energy storage vector we estimate that 150 TWh of seasonal storage is required to replace seasonal variations in natural gas production. Large-scale storage is best suited to porous rock reservoirs. We present a method to quantify the hydrogen storage capacity of gas fields and saline aquifers using data previously used to assess CO2 storage potential. We calculate a P50 value of 6900 TWh of working gas capacity in gas fields and 2200 TWh in saline aquifers on the UK continental shelf assuming a cushion gas requirement of 50%. Sensitivity analysis reveals low temperature storage sites with sealing rocks that can withstand high pressures are ideal sites. Gas fields in the Southern North Sea could utilise existing infrastructure and large offshore wind developments to develop large-scale offshore hydrogen production.
Numerical Simulation on the Thermal Dynamic Behavior of Liquid Hydrogen in a Storage Tank for Trailers
Oct 2022
Publication
In the present study a numerical model was established to investigate the thermal dynamic behavior of liquid hydrogen in a 40-foot ISO tank. The volume of fluids (VOF) method was applied to capture the liquid surface and a phase change model was used to describe the evaporation phenomenon of hydrogen. The mesh independence analysis and the experimental validation have been made. Under different filling levels motion statuses and heat leakage conditions the variations in pressure and temperature of the tank were investigated. The pressure of 90% filling level case was reduced by 12.09% compared to the 50% case. Besides the pressure of the sloshing condition has increased twofold contrasted with the stationary one and thermal stratification disappeared. Additionally 16.67 minutes were taken for the ullage pressure to reach around 1MPa in emergencies of being extremely heated. Some valuable conclusions and suggestions for the transportation of liquid hydrogen arrived. Those could be the references to predict the release time of boil-off hydrogen and primarily support for gas-releasing control strategies.
The Influence of the First Filling Period Length and Reservoir Level Depth on the Operation of Underground Hydrogen Storage in a Deep Aquifer
Sep 2022
Publication
Underground storage is a method of storing large amounts of renewable energy that can be converted into hydrogen. One of the fundamental problems associated with this process concerns determining the timing and amount of injected gas in the first filling period for the operation of an underground storage facility. Ascertaining the hydrogen flow rate is essential to ensure that the capillary and fracturing pressures are not exceeded. The value of the flow rate was assessed by modelling the injection of hydrogen into a deep aquifer. The best initial H2 injection period was found to be five months. The volume of the cushion gas and the total storage capacity expanded with the extension of the first filling period length. The working capacity grew as the depth increased reaching maximum values at depths of approximately 1200e1400 m. This depth was considered optimal for storing hydrogen in the analysed structure.
Increasing the Energy Efficiency of Gas Boosters for Hydrogen Storage and for Refueling Stations
Feb 2023
Publication
A new electrically driven gas booster is described as an alternative to the classical air-driven gas boosters known for their poor energetic efficiency. These boosters are used in small scale Hydrogen storage facilities and in refueling stations for Hydrogen vehicles. In such applications the overall energy count is of significance and must include the efficiency of the compression stage. The proposed system uses an electric motor instead of the pneumatic actuator and increases the total efficiency of the compression process. Two mechanical principles are studied for the transformation of the rotational motion of the motor to the linear displacement of the compressor pistons. The strongly fluctuating power of the compressor is smoothed by an active capacitive auxiliary storage device connected to the DC circuit of the power converter. The proposed system has been verified by numeric simulation including the thermodynamic phenomena the kinetics of the new compressor drive and the the operation of the circuits of the power smoothing system.
Refurbishment of Natural Gas Pipelines towards 100% Hydrogen—A Thermodynamic-Based Analysis
Dec 2022
Publication
Hydrogen is a key enabler of a sustainable society. Refurbishment of the existing natural gas infrastructure for up to 100% H2 is considered one of the most energy- and resource-efficient energy transportation methods. The question remains whether the transportation of 100% H2 with reasonable adaptions of the infrastructure and comparable energy amounts to natural gas is possible. The well-known critical components for refurbishment such as increased compressor power reduced linepack as well as pipeline transport efficiencies and their influencing factors were considered based on thermodynamic calculations with a step-by-step overview. A H2 content of 20–30% results in comparable operation parameters to pure natural gas. In addition to transport in pipelines decentralized H2 production will also play an important role in addressing future demands.
Combined Effects of Stress and Temperature on Hydrogen Diffusion in Non-hydride Forming Alloys Applied in Gas Turbines
Jul 2022
Publication
Hydrogen plays a vital role in the utilisation of renewable energy but ingress and diffusion of hydrogen in a gas turbine can induce hydrogen embrittlement on its metallic components. This paper aims to investigate the hydrogen transport in a non-hydride forming alloy such as Alloy 690 used in gas turbines inspired by service conditions of turbine blades i.e. under the combined effects of stress and temperature. An appropriate hydrogen transport equation is formulated accounting for both stress and temperature distributions of the domain in the non-hydride forming alloy. Finite element (FE) analyses are performed to predict steady-state hydrogen distribution in lattice sites and dislocation traps of a double notched specimen under constant tensile load and various temperature fields. Results demonstrate that the lattice hydrogen concentration is very sensitive to the temperature gradients whilst the stress concentration only slightly increases local lattice hydrogen concentration. The combined effects of stress and temperature result in the highest concentration of the dislocation trapped hydrogen in low-temperature regions although the plastic strain is only at a moderate level. Our results suggest that temperature gradients and stress concentrations in turbine blades due to cooling channels and holes make the relatively low-temperature regions susceptible to hydrogen embrittlement.
Hydrogen-Enriched Compressed Natural Gas Network Simulation for Consuming Green Hydrogen Considering the Hydrogen Diffusion Process
Sep 2022
Publication
Transporting green hydrogen by existing natural gas networks has become a practical means to accommodate curtailed wind and solar power. Restricted by pipe materials and pressure levels there is an upper limit on the hydrogen blending ratio of hydrogen-enriched compressed natural gas (HCNG) that can be transported by natural gas pipelines which affects whether the natural gas network can supply energy safely and reliably. To this end this paper investigates the effects of the intermittent and fluctuating green hydrogen produced by different types of renewable energy on the dynamic distribution of hydrogen concentration after it is blended into natural gas pipelines. Based on the isothermal steady-state simulation results of the natural gas network two convection–diffusion models for the dynamic simulation of hydrogen injections are proposed. Finally the dynamic changes of hydrogen concentration in the pipelines under scenarios of multiple green hydrogen types and multiple injection nodes are simulated on a seven-node natural gas network. The simulation results indicate that compared with the solar-power-dominated hydrogen productionblending scenario the hydrogen concentrations in the natural gas pipelines are more uniformly distributed in the wind-power-dominated scenario and the solar–wind power balance scenario. To be specific in the solar-power-dominated scenario the hydrogen concentration exceeds the limit for more time whilst the overall hydrogen production is low and the local hydrogen concentration in the natural gas network exceeds the limit for nearly 50% of the time in a day. By comparison in the wind-power-dominated scenario all pipelines can work under safe conditions. The hydrogen concentration overrun time in the solar–wind power balance scenario is also improved compared with the solar-power-dominated scenario and the limit-exceeding time of the hydrogen concentration in Pipe 5 and Pipe 6 is reduced to 91.24% and 91.99% of the solar-power-dominated scenario. This work can help verify the day-ahead scheduling strategy of the electricity-HCNG integrated energy system (IES) and provide a reference for the design of local hydrogen production-blending systems.
Inspection of Coated Hydrogen Transportation Pipelines
Sep 2023
Publication
The growing need for hydrogen indicates that there is likely to be a demand for transporting hydrogen. Hydrogen pipelines are an economical option but the issue of hydrogen damage to pipeline steels needs to be studied and investigated. So far limited research has been dedicated to determining how the choice of inspection method for pipeline integrity management changes depending on the presence of a coating. Thus this review aims to evaluate the effectiveness of inspection methods specifically for detecting the defects formed uniquely in coated hydrogen pipelines. The discussion will begin with a background of hydrogen pipelines and the common defects seen in these pipelines. This will also include topics such as blended hydrogen-natural gas pipelines. After which the focus will shift to pipeline integrity management methods and the effectiveness of current inspection methods in the context of standards such as ASME B31.12 and BS 7910. The discussion will conclude with a summary of newly available inspection methods and future research directions.
Metal-Hydride-Based Hydrogen Storage as Potential Heat Source for the Cold Start of PEM FC in Hydrogen-Powered Coaches: A Comparative Study of Various Materials and Thermal Management Techniques
Nov 2022
Publication
The successful and fast start-up of proton exchange membrane fuel cells (PEMFCs) at subfreezing temperatures (cold start) is very important for the use of PEMFCs as energy sources for automotive applications. The effective thermal management of PEMFCs is of major importance. When hydrogen is stored in hydride-forming intermetallics significant amounts of heat are released due to the exothermic nature of the reaction. This excess of heat can potentially be used for PEMFC thermal management and to accelerate the cold start. In the current work this possibility is extensively studied. Three hydride-forming intermetallics are introduced and their hydrogenation behavior is evaluated. In addition five thermal management scenarios of the metal hydride beds are studied in order to enhance the kinetics of the hydrogenation. The optimum combination of the intermetallic hydrogenation behavior weight and complexity of the thermal management system was chosen for the study of thermal coupling with the PEMFCs. A 1D GT-SUITE model was built to stimulate the thermal coupling of a 100 kW fuel cell stack with the metal hydride. The results show that the use of the heat from the metal hydride system was able to reduce the cold start by up to 8.2%.
Investigating Hydrogen-Based Non-Conventional Storage for PV Power in Eco-Energetic Optimization of a Multi-Energy System
Dec 2021
Publication
Through the integration of multiple energy carriers with related technologies multi-energy systems (MES) can exploit the synergies coming from their interplay for several benefits towards decarbonization. In such a context inclusion of Power-to-X technologies in periods of excess renewable electricity supply removes the need for curtailment of renewable electricity generation. In order to achieve the environmental benefits of MES without neglecting their economic feasibility the optimal design problem is as crucial as challenging and requires the adoption of a multi-objective approach. This paper extends the results of a previous work by investigating hydrogen-based non-conventional storage for PV power in the eco-energetic optimization of an MES. The system under study consists of a reversible fuel cell (r-SOC) photovoltaic (PV) electric heat pump absorption chiller and thermal storage and allows satisfying the multi-energy needs of a residential end-user. A multi-objective linear problem is established to find the optimal MES configuration including the sizes of the involved technologies with the goal of reducing the total annual cost and the fossil primary energy input. Simulation results are compared with those obtained in previous work with a conventional nanogrid where a combined heat and power (CHP) system with gas-fired internal combustion engine and a battery were present instead of an r-SOC. The optimized configuration of the non-conventional nanogrid allows achieving a maximum primary energy reduction amounting to 66.3% compared to the conventional nanogrid. In the face of the environmental benefits the non-conventional nanogrid leads to an increase in total annual costs which compared to the conventional nanogrid is in the range of 41–65%.
Research on the Sealing Mechanism of Split-Liner High-Pressure Hydrogen Storage Cylinders
Mar 2024
Publication
Hydrogen storage is a crucial factor that limits the development of hydrogen energy. This paper proposes using a split liner for the inner structure of a hydrogen storage cylinder. A self-tightening seal is employed to address the sealing problem between the head and the barrel. The feasibility of this structure is demonstrated through hydraulic pressure experiments. The influence laws of the O-ring compression rate the distance from the straight edge section of the head to the sealing groove and the thickness of the head on the sealing performance of gas cylinders in this sealing structure are revealed using finite elements analysis. The results show that when the gas cylinder is subjected to medium internal pressure the maximum contact stress on the O-ring extrusion deformation sealing surface is greater than the medium pressure. There is sufficient contact width that is the arc length of the part where the stress on the O-ring contact surface is greater than the medium pressure so that it can form a good sealing condition. At the same time increasing the compression ratio of the O-ring and the head’s thickness will help improve the sealing performance and reducing the distance from the straight edge section of the head to the sealing groove will also improve the sealing performance.
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