France

Recent advances on synthesis characterization and hydrogen absorption properties of ultrasmall metal nanoparticles (defined here as objects with average size ≤3 nm) are briefly reviewed in the first part of this work. The experimental challenges encountered in performing accurate measurements of hydrogen absorption in Mg- and noble metal-based ultrasmall nanoparticles are addressed. The second part of this work reports original results obtained for ultrasmall bulk-immiscible Pd–Rh nanoparticles. Carbon-supported Pd–Rh nanoalloys in the whole binary chemical composition range have been successfully prepared by liquid impregnation method followed by reduction at 300°C. EXAFS investigations suggested that the local structure of these nanoalloys is partially segregated into Rh-rich core and Pd-rich surface coexisting within the same nanoparticles. Downsizing to ultrasmall dimensions completely suppresses the hydride formation in Pd-rich nanoalloys at ambient conditions contrary to bulk and larger nanosized (5–6 nm) counterparts. The ultrasmall Pd90Rh10 nanoalloy can absorb hydrogen-forming solid solutions under these conditions as suggested by in situ X-ray diffraction (XRD). Apart from this composition common laboratory techniques such as in situ XRD DSC and PCI failed to clarify the hydrogen interaction mechanism: either adsorption on developed surfaces or both adsorption and absorption with formation of solid solutions. Concluding insights were brought by in situ EXAFS experiments at synchrotron: ultrasmall Pd₇₅Rh₂₅ and Pd₅₀Rh₅₀ nanoalloys absorb hydrogen-forming solid solutions at ambient conditions. Moreover the hydrogen solubility in these solid solutions is higher with increasing Pd content and this trend can be understood in terms of hydrogen preferential occupation in the Pd-rich regions as suggested by in situ EXAFS. The Rh-rich nanoalloys (Pd₂₅Rh₇₅ and Pd₁₀Rh₉₀) only adsorb hydrogen on the developed surface of ultrasmall nanoparticles. In summary in situ characterization techniques carried out at large-scale facilities are unique and powerful tools for in-depth investigation of hydrogen interaction with ultrasmall nanoparticles at local level.

To address the climate emergency France is committed to achieving carbon neutrality by 2050. It plans to significantly increase the contribution of renewable energy in its energy mix. The share of renewable energy in its electricity production which amounts to 25.5% in 2020 should reach at least 40% in 2030. This growth poses several new challenges that require policy makers and regulators to act on the technological changes and expanding need for flexibility in power systems. This document presents the main strategies and projects developed in France as well as various recommendations to accompany and support its energy transition policy.

A polyethylene (PE) liner is the basic element in high-pressure type 4 composite vessels designed for hydrogen or compressed natural gas (CNG) storage systems. Liner defects may result in the elimination of the whole vessel from use which is very expensive both at the manufacturing and exploitation stage. The goal is therefore the development of efficient non-destructive testing (NDT) methods to test a liner immediately after its manufacturing before applying a composite reinforcement. It should be noted that the current regulations codes and standards (RC&S) do not specify liner testing methods after manufacturing. It was considered especially important to find a way of locating and assessing the size of air bubbles and inclusions and the field of deformations in liner walls. It was also expected that these methods would be easily applicable to mass-produced liners. The paper proposes the use of three optical methods namely visual inspection digital image correlation (DIC) and optical fiber sensing based on Bragg gratings (FBG). Deformation measurements are validated with finite element analysis (FEA). The tested object was a prototype of a hydrogen liner for high-pressure storage (700 bar). The mentioned optical methods were used to identify defects and measure deformations.

While significant increase in turbulent burning rate in lean premixed flames of hydrogen or hydrogen-containing fuel blends is well documented in various experiments and can be explained by highlighting local diffusional-thermal effects capabilities of the vast majority of available models of turbulent combustion for predicting this increase have not yet been documented in numerical simulations. To fill this knowledge gap a well-validated Turbulent Flame Closure (TFC) model of the influence of turbulence on premixed combustion which however does not address the diffusional-thermal effects is combined with the leading point concept which highlights strongly perturbed leading flame kernels whose local structure and burning rate are significantly affected by the diffusional-thermal effects. More specifically within the framework of the leading point concept local consumption velocity is computed in extremely strained laminar flames by adopting detailed combustion chemistry and subsequently the computed velocity is used as an input parameter of the TFC model. The combined model is tested in RANS simulations of highly turbulent lean syngas-air flames that were experimentally investigated at Georgia Tech. The tests are performed for four different values of the inlet rms turbulent velocities different turbulence length scales normal and elevated (up to 10 atm) pressures various H₂/CO ratios ranging from 30/70 to 90/10 and various equivalence ratios ranging from 0.40 to 0.80. All in all the performed 33 tests indicate that the studied combination of the leading point concept and the TFC model can predict well-pronounced diffusional-thermal effects in lean highly turbulent syngas-air flames with these results being obtained using the same value of a single constant of the combined model in all cases. In particular the model well predicts a significant increase in the bulk turbulent consumption velocity when increasing the H₂/CO ratio but retaining the same value of the laminar flame speed.

Hydrogen and its interaction with metal oxide surfaces is of major importance for a wide range of research and applied fields spanning from catalysis energy storage microelectronics to metallurgy. This paper reviews state of the art of first principles calculations on the well-known ruthenium oxide (RuO₂) surface in its (110) orientation and its interaction with hydrogen. In addition to it the paper also fills gaps in knowledge with new calculations and results on the (001) surface. Bulk and surface interactions are thoroughly reviewed. This includes systematic analysis of adsorption sites local agglomeration propensity of hydrogen and migration pathways in which literature data and their potential deviations are explained. We notably discuss novel results on propensity for agglomeration of hydrogen within bulk channels [001] oriented in which the proton-like behavior of adsorbed hydrogen hinders further agglomeration in adjacent channels. The paper brings new insights into the migration pathways on the surface and in bulk both exhibiting preferential diffusion paths along the [001] direction. The paper finally investigates the subsurface region. We show that while the subsurface has more stable sites for adsorption compared to bulk its accessibility from the surface shows prohibitive activation barriers inhibiting penetration into subsurface and bulk. We further calculate and discuss adsorption and penetration processes on the alternative RuO₂ (001) surface.

Due to its characteristics hydrogen is considered the energy carrier of the future. Its use as a fuel generates reduced pollution as if burned it almost exclusively produces water vapor. Hydrogen can be produced from numerous sources both of fossil and renewable origin and with as many production processes which can use renewable or non-renewable energy sources. To achieve carbon neutrality the sources must necessarily be renewable and the production processes themselves must use renewable energy sources. In this review article the main characteristics of the most used hydrogen production methods are summarized mainly focusing on renewable feedstocks furthermore a series of relevant articles published in the last year are reviewed. The production methods are grouped according to the type of energy they use; and at the end of each section the strengths and limitations of the processes are highlighted. The conclusions compare the main characteristics of the production processes studied and contextualize their possible use.

Promoted by national and European investment plans promoting the use of hydrogen as energy carrier the number of Gaseous Hydrogen Fueling Station (or GHFS) has been growing up quite significantly over the past years. Considering the new possible hazards and the related accidents induced by these installations like seen in 2019 in Norway this paper presents a risk assessment of a typical GHFS using the same methodology as the one required in France by the authorities for Seveso facilities. The fact that a hydrogen fueling station could be used by a public not particularly trained to handle hydrogen underlines the importance of this risk assessment. In this article typical components related to GHFS (dispenser high pressure storage compressor low pressure storage) are listed and the hazard potentials linked to these components and the substances involved are identified. Based on these elements and an accidentology a risk analysis has been conducted in order to identify all accidental situations that could occur. The workflow included a detailed risk assessment consisting in modeling the thermal and explosion effects of all hazardous phenomena and in assessing the probability of occurrence for these scenarios. Regarding possible mitigation measures the study was based on an international benchmark for codes and standards made for GFHS. These preliminary outcomes of this study may be useful for any designer and/or owner of a GFHS.

The circular economy is a decisive strategy for reconciling economic development and the environment. In France the CE was introduced into the law in 2015 with the objective of closing the loop. The legislation also delegates energy policy towards the French regions by granting them the jurisdiction to directly plan the energy–climate issues on their territory and to develop local energy resources. Thereby the SUD PACA region has redefined its objectives and targeted carbon neutrality and the transition to a CE by 2050. To study this transition we developed a TIMESPACA optimization model. The results show that following a CE perspective to develop a local energy system could contribute to reducing CO2 emissions by 50% in final energy consumption and reaching almost free electricity production. To obtain greater reductions the development of the regional energy systems should follow a careful policy design favoring the transition to low energy-consuming behavior and the strategical allocation of resources across the different sectors. Biomethane should be allocated to the buildings and industrial sector while hydrogen should be deployed for buses and freight transport vehicles.

The absence of contaminants in the hydrogen delivered at the hydrogen refuelling station is critical to ensure the length life of FCEV. Hydrogen quality has to be ensured according to the two international standards ISO 14687–2:2012 and ISO/DIS 19880-8. Amount fraction of contaminants from the two hydrogen production processes steam methane reforming and PEM water electrolyser is not clearly documented. Twenty five different hydrogen samples were taken and analysed for all contaminants listed in ISO 14687-2. The first results of hydrogen quality from production processes: PEM water electrolysis with TSA and SMR with PSA are presented. The results on more than 16 different plants or occasions demonstrated that in all cases the 13 compounds listed in ISO 14687 were below the threshold of the international standards. Several contaminated hydrogen samples demonstrated the needs for validated and standardised sampling system and procedure. The results validated the probability of contaminants presence proposed in ISO/DIS 19880-8. It will support the implementation of ISO/ DIS 19880-8 and the development of hydrogen quality control monitoring plan. It is recommended to extend the study to other production method (i.e. alkaline electrolysis) the HRS supply chain (i.e. compressor) to support the technology growth.

The present work is concerned with the evaluation of the tightness of the components located on domestic and commercial gas lines from the gas meter to the end user appliance in presence of a mixture 40%H2+60%CH4 at 35 mbar. The components were taken from installations being used currently in Germany Denmark Belgium and France. The current standard methods to evaluate natural gas distribution tightness propose testing duration of several minutes. In this work the components tightness was first evaluated using such standard methods before carrying out tests on longer period of time and evaluate the potential influence of time and the results were compared to admissible leakage rates for natural gas in distribution network and in appliances.