Transmission, Distribution & Storage

Tropical climate is characterized by hot temperatures throughout the year. In areas subject to this climate air conditioning represents an important share of total energy consumption. In some tropical islands there is no electric grid; in these cases electricity is often provided by diesel generators. In this study in order to decarbonize electricity and cooling production and to improve autonomy in a standalone application a microgrid producing combined cooling and electrical power was proposed. The presented system was composed of photovoltaic panels a battery an electrolyzer a hydrogen tank a fuel cell power converters a heat pump electrical loads and an adsorption cooling system. Electricity production and storage were provided by photovoltaic panels and a hydrogen storage system respectively while cooling production and storage were achieved using a heat pump and an adsorption cooling system respectively. The standalone application presented was a single house located in Tahiti French Polynesia. In this paper the system as a whole is presented. Then the interaction between each element is described and a model of the system is presented. Thirdly the energy and power management required in order to meet electrical and thermal needs are presented. Then the results of the control strategy are presented. The results showed that the adsorption cooling system provided 53% of the cooling demand. The use of the adsorption cooling system reduced the needed photovoltaic panel area the use of the electrolyzer and the use of the fuel cell by more than 60% and reduced energy losses by 7% (compared to a classic heat pump) for air conditioning.

This paper authored by eleven gas infrastructure companies and supported by Guidehouse describes how a dedicated hydrogen infrastructure can be created in

a significant part of the EU between 2030 and 2040 requiring work to start during the 2020s. The hydrogen infrastructure as proposed in this paper fits well with the ambitions of the EU Hydrogen Strategy and the Energy System Integration Strategy plus it aligns well with the goals of the recently announced Clean Hydrogen Alliance to scale up hydrogen enabled by hydrogen transport. Hydrogen clearly gains momentum and this paper aims to provide a contribution towards accelerating a large scale-up of hydrogen by enabling its transport from supply to demand across Europe.

This paper analyses the likely routes across Europe by 2030 2035 and 2040. The included maps show the suggested topology of hydrogen pipelines in ten European countries: Germany France Italy Spain the Netherlands Belgium Czech Republic Denmark Sweden and Switzerland.

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The need for energy and water security on islands has led to an increase in the use of wind power. However the intermittent nature of wind generation means it needs to be coupled with a storage system. Motivated by this two different models of surplus energy storage systems are investigated in this paper. In both models renewable wind energy is provided by a wind farm. In the first model a pumped hydro storage system (PHS) is used for surplus energy storage while in the second scenario a hybrid pumped hydrogen storage system (HPHS) is applied consisting of a PHS and a hydrogen storage system. The goal of this study is to compare the single and the hybrid storage system to fulfill the energy requirements of the island’s electricity load and desalination demands for domestic and irrigation water. The cost of energy (COE) is 0.287 EUR/kWh for PHS and 0.360 EUR/kWh for HPHS while the loss of load probability (LOLP) is 22.65% for PHS and 19.47% for HPHS. Sensitivity analysis shows that wind speed is the key parameter that most affects COE cost of water (COW) and LOLP indices while temperature affects the results the least.

A key issue in understanding and effectively managing hydrogen embrittlement in complex alloys is identifying and exploiting the critical role of the various defects involved. A chemo-mechanical model for hydrogen diffusion is developed taking into account stress gradients in the material as well as microstructural trapping sites such as grain boundaries and dislocations. In particular the energetic parameters used in this coupled approach are determined from ab initio calculations. Complementary experimental investigations that are presented show that a numerical approach capable of massive scale-bridging up to the macroscale is required. Due to the wide range of length scales accounted for we apply homogenisation schemes for the hydrogen concentration to reach simulation dimensions comparable to metallurgical process scales. Via a representative volume element approach an ab initio based scale bridging description of dislocation-induced hydrogen aggregation is easily accessible. When we extend the representative volume approach to also include an analytical approximation for the ab initio based description of grain boundaries we find conceptual limitations that hinder a quantitative comparison to experimental data in the current stage. Based on this understanding the development of improved strategies for further efficient scale bridging approaches is foreseen.

The report analyses the technical impacts to end-users of natural gas in Australian distribution networks when up to 10% hydrogen (by volume) is mixed with natural gas.



The full report can be found at this link.

The objective of this project is to take into account the mechanical constraints formed by diffusion of hydrogen or tritium in watertight palladium alloy cathode. To know the origin of these it was necessary to discriminating the damaging effects encountered. Effectively hydrogen and isotope induce deformation embrittlement stress corrosion cracking and cathodic corrosion in different regions of cathode. Palladium can be alloyed with silver or yttrium to favourably increase diffusion and reduce these constraints. Effects of electrochemical factors temperature cathode structure adsorbed transient complex of palladium and porous material support are given to estimate and to limit possible damage.

The possibility of using hydrogen as a reliable energy carrier for both stationary and mobile applications has gained renewed interest in recent years due to improvements in high temperature fuel cells and a reduction in hydrogen production costs. However a number of challenges remain and new media are needed that are capable of safely storing hydrogen with high gravimetric and volumetric densities. Metal hydrides and complex metal hydrides offer some hope of overcoming these challenges; however many of the high capacity “reversible” hydrides exhibit a large endothermic decomposition enthalpy making it difficult to release the hydrogen at low temperatures. On the other hand the metastable hydrides are characterized by a low reaction enthalpy and a decomposition reaction that is thermodynamically favorable under ambient conditions. The rapid low temperature hydrogen evolution rates that can be achieved with these materials offer much promise for mobile PEM fuel cell applications. However a critical challenge exists to develop new methods to regenerate these hydrides directly from the reactants and hydrogen gas. This spotlight paper presents an overview of some of the metastable metal hydrides for hydrogen storage and a few new approaches being investigated to address the key challenges associated with these materials.

Hydrogen embrittlement (HE) is a critical issue that affects the reliability of hydrogenation reactors. The hydrogen diffusivity/trap characteristics of 2.25Cr-1Mo-0.25V steel are important parameters mainly used to study the HE mechanism of steel alloys. In this work the hydrogen diffusivity/trap characteristics of heat-treated (annealed) and untreated 2.25Cr-1Mo-0.25V steel were studied using an electrochemical permeation method. The microstructures of both 2.25Cr-1Mo-0.25V steels were investigated by metallurgical microscopy. The effect of cementite on the hydrogen diffusivity/trap mechanisms was studied using thermodynamics-based and Lennard–Jones potential theories. The results revealed that the cementite located at the grain boundaries and at the interfaces of lath ferrite served as a kind of hydrogen trap (i.e. an irreversible hydrogen trap). In addition hydrogen was transported from ferrite to cementite via up-hill diffusion thereby supporting the hypothesis of cementite acting as a hydrogen trap.

In this study electrochemical measurements immersion tests and slow strain rate tensile (SSRT) tests were applied to investigate the electrochemical and stress corrosion cracking (SCC) behavior of X70 steel in simulated seawater with the interference of different alternating current (AC) densities. The results indicate that AC significantly strengthens the cathodic reaction especially the oxygen reduction reaction. Simultaneously hydrogen evolution reaction occurs when the limiting diffusion current density of oxygen reaches and thus icorr sharply increases with the increase in AC density. Additionally when AC is imposed the X70 steel exhibits higher SCC susceptibility in the simulated seawater and the susceptibility increases with the increasing AC density. The SCC mechanism is controlled by both anodic dissolution (AD) and hydrogen embrittlement (HE) with the interference of AC.

A flake is a crack that is induced by trapped hydrogen within steel. To study its formation mechanism previous studies mostly focused on the formation process and magnitude of hydrogen pressure in hydrogen traps such as cavities and cracks. However according to recent studies the hydrogen leads to the decline of the mechanical properties of steel which is known as hydrogen embrittlement is another reason for flake formation. In addition the phenomenon of stress induced hydrogen uphill diffusion should not be neglected. All of the three behaviors are at work simultaneously. In order to further explore the formation mechanism of flakes in steel the process of flake initiation and growth were studied with the following three coupling factors: trap hydrogen pressure hydrogen embrittlement and stress induced hydrogen re-distribution. The analysis model was established using the finite element method and a crack whose radius is 0.5 mm was set in its center. The cohesive method and Bilinear Traction Separate Law (BTSL) were used to address the coupling effect. The results show that trap hydrogen pressure is the main driving force for flake formation. After the high hydrogen pressure was generated around the trap a stress field formed. In addition the trap is the center of stress concentration. Then hydrogen is concentrated in a distribution around this trap and most of the steel mechanical properties are reduced. The trap size is a key factor for defining the critical hydrogen content for flake formation and propagation. However when the trap size exceeds the specified value the critical hydrogen content does not change any more. As for the crack whose radius is 0.5 mm the critical hydrogen content of Cr5VMo steel is 2.2 ppm which is much closer to the maximum safe hydrogen concentration of 2.0 ppm used in China. The work presented in this article increases our understanding of flake formation and propagation mechanisms in steel.