France

Hydrogen is a key energy carrier that could play a crucial role in the transition to a low-carbon economy. Hydrogen-related technologies are considered flexible solutions to support the large-scale implementation of intermittent energy supply from renewable sources by using renewable energy to generate green hydrogen during periods of low demand. Therefore a short-term increase in demand for hydrogen as an energy carrier and an increase in hydrogen production are expected to drive demand for large-scale storage facilities to ensure continuous availability. Owing to the large potential available storage space underground hydrogen storage offers a viable solution for the long-term storage of large amounts of energy. This study presents the results of a survey of potential underground hydrogen storage sites in Italy carried out within the H2020 EU Hystories “Hydrogen Storage In European Subsurface” project. The objective of this work was to clarify the feasibility of the implementation of large-scale storage of green hydrogen in depleted hydrocarbon fields and saline aquifers. By analysing publicly available data mainly well stratigraphy and logs we were able to identify onshore and offshore storage sites in Italy. The hydrogen storage capacity in depleted gas fields currently used for natural gas storage was estimated to be around 69.2 TWh.

Urban air mobility (UAM) defined as safe and efficient air traffic operations in a metropolitan area for manned aircraft and unmanned aircraft systems is being researched and developed by industry academia and government. This kind of mobility offers an opportunity to construct a green and sustainable sub-sector building upon the lessons learned over decades by aviation. Thanks to their non-polluting operation and simple air traffic management electric vertical take-off and landing (eVTOL) aircraft technologies are currently being developed and experimented with for this purpose. However to successfully complete the certification and commercialization stage several challenges need to be overcome particularly in terms of performance such as flight time and endurance and reliability. In this paper a fast methodology for sizing and selecting the propulsion chain components of an eVTOL multirotor aerial vehicle was developed and validated on a reduced-scale prototype of an electric multirotor vehicle with a GTOW of 15 kg. This methodology is associated with a comparative study of energy storage system configurations in order to assess their effect on the flight time of the aerial vehicle. First the optimal pair motor/propeller was selected using a global nonlinear optimization in order to maximize the specific efficiency of these components. Second five energy storage technologies were sized in order to evaluate their influence on the aerial vehicle flight time. Finally based on this sizing process the optimized propulsion chain gross take-off weight (GTOW) was evaluated for each energy storage configuration using regression-based methods based on propulsion chain supplier data.

The main purpose of this article is to provide a short review of proton exchange membrane electrolyzer (PEMEL) modeling used for power electronics control. So far three types of PEMEL modeling have been adopted in the literature: resistive load static load (including an equivalent resistance series-connected with a DC voltage generator representing the reversible voltage) and dynamic load (taking into consideration the dynamics both at the anode and the cathode). The modeling of the load is crucial for control purposes since it may have an impact on the performance of the system. This article aims at providing essential information and comparing the different load modeling.

The Global Hydrogen Review is an annual publication by the International Energy Agency that tracks hydrogen production and demand worldwide as well as progress in critical areas such as infrastructure development trade policy regulation investments and innovation. The report is an output of the Clean Energy Ministerial Hydrogen Initiative and is intended to inform energy sector stakeholders on the status and future prospects of hydrogen while also informing discussions at the Hydrogen Energy Ministerial Meeting organised by Japan. Focusing on hydrogen’s potentially major role in meeting international energy and climate goals the Review aims to help decision makers fine-tune strategies to attract investment and facilitate deployment of hydrogen technologies at the same time as creating demand for hydrogen and hydrogen-based fuels. It compares real-world developments with the stated ambitions of government and industry. This year’s report includes a focus on demand creation for low-emission hydrogen. Global hydrogen use is increasing but demand remains so far concentrated in traditional uses in refining and the chemical industry and mostly met by hydrogen produced from unabated fossil fuels. To meet climate ambitions there is an urgent need to switch hydrogen use in existing applications to low-emission hydrogen and to expand use to new applications in heavy industry or long-distance transport.

To contribute to a more diverse and efficient energy infrastructure large quantities of hydrogen are requested for industries (e.g. mining refining fertilizers…). These applications need large scale facilities such as dozens of electrolyzer stacks from atmospheric pressure to 30 bar with a total capacity ranging from 100 up to 400 MW and associated hydrogen storage from a few to 50 tons.

Local use can be fed by electrolyzer in 20 feet container and stored in bundles with small volumes. Nevertheless industrial applications can request much bigger capacity of production which are generally located in buildings. The different technologies available for the production of hydrogen at large scale are alkaline or PEM electrolyzer with for example 100 MW capacity in a building of 20000 m3 and hydrogen stored in tube trailers or other fixed hydrogen storage solution with large volumes.

These applications led to the use of hydrogen inside large but confined spaces with the risk of fire and explosion in case of loss of containment followed by ignition. This can lead to severe consequences on asset workers and public due to the large inventories of hydrogen handled.

This article aims to provide an overview of the strategy to safely design large scale hydrogen production facilities in buildings through benchmarks based on projects and literature reviews best practices & standards regulations. It is completed by a risk assessment taking into consideration hydrogen behavior and influence of different parameters in dispersion and explosion in large buildings.

This article provides recommendations for hydrogen project stakeholders to perform informed-based decisions for designing large scale production buildings. It includes safety measures as reducing hydrogen inventories inside building allocating clearance around electrolyzer stacks implementing early detection and isolation devices and building geometry to avoid hydrogen accumulation.

This study explores the integration and optimization of a hydrogen-based energy system emphasizing the use of metal hydride (MH) storage coupled with Proton Exchange Membrane Fuel Cell Micro Combined Heat and Power (PEMFC MCHP) system for residential applications. MH storage coupled to a heat pump operates at charging and discharging pressures of 10 bar. COMSOL model in 6.1 version using heat transfer in solids and fluids in brinkman equations modules is validated by experimental data and uses machine learning (Feedforward Neural Networks) for predictive modeling of MH dynamics. Smaller 500 NL tanks were found to have high mass-specific heat demand but faster hydrogen gas kinetics reaching (~77 % capacity in one hour) whereas larger 6500 NL (~57 %/hour) absorb hydrogen gas more gradually but reduce thermal management intensities. Using 13 × 500 NL tanks reach ~25 % discharge in 1 h but require ~2170 Wh heating whereas one 6500 NL tank only attains ~48.5 % discharge yet uses ~1750 Wh illustrating a trade-off between faster kinetics and lower thermal load. A genetic algorithm identified an optimal configuration of two 6500 NL tanks that covered ~68 % of total hydrogen gas consumption and 65 % of production at a maximum of 2.4 kW heating and 2.45 kW cooling. Additional comparisons with 170 bar compressed storage revealed lower instantaneous thermal requirements for high-pressure gas tanks. Adding a 170 bar compressed H2 alongside the 10 bar MH system hydrogen gas coverage rose from ~70 % to ~97 % when storage expanded to 200 Nm3 but at the cost of higher compression energy. The proposed MH-based approach especially at moderate pressures with carefully planned tank geometries achieves enhanced operational flexibility for a residential 120 m2 building’s space heating and hot water while machine learning optimizations further refine charge–discharge performance.

In the pursuit of establishing a sustainable fuel cell (FC) energy system this review highlights the necessity of examining the operational principles technical details environmental consequences and economic concerns collectively. By adopting an integrated approach the review research into various fuel cells types extending their applications beyond transportation and evaluating their potential for seamless integration into sustainable practices. A detailed analysis of the technical aspects including FC membranes performance and applications is presented. The environmental impact of hydrogen generation through fuel cell/electrolyzer is quantitatively assessed emphasizing a comparative emission footprint against traditional hydrogen generation methods. Economic considerations of fuel cell technology adoption are explored through an extensive examination of market growth and forecasts and investments into the FC systems. Some flagship commercial projects of FC technology are also discussed along with their future prospective. The article concludes with a thorough analysis of challenges associated with FC adoption encompassing membrane research performance hurdles infrastructure development and application-specific challenges. This all-round review serves as an indispensable tool for academicians and policymakers providing a directed and comprehensive FC perspective.

Natural hydrogen (H2) holds promising potential as a clean energy source but its exploration remains challenging due to limited knowledge and a lack of quantitative tools. In this context identifying active H2 seepage areas is crucial for advancing exploration efforts. Here we focus on sub-circular depressions (SCDs) that often mark high H2 concentration in soils thought to correspond to deeper fluxes seeping at the surface making them promising targets for exploration. Coupling open-access Google Earth© images and in-field H2 measurement data an artificial intelligence model was trained to detect seepage zones. The model achieves an average precision of 95 % detects and maps seepage zones in new regions like Kazakhstan and South Africa highlighting its potential for global application. Moreover preliminary spatial analyses show that geological features control the distribution of H2-SCDs that can emit billions of tons of H2 at the scale of a sedimentary basin. This study paves the way for a faster and more efficient methodology for selecting H2 exploration targets. Plain Language Summary. Natural hydrogen is a promising clean energy source but it remains difficult to explore due to a lack of accessible tools. In this study we used free satellite images (Google Earth©) and in-field hydrogen measurements to identify specific surface features - small sub-circular depressions (SCDs) - that often mark areas where hydrogen is seeping from underground. We trained an artificial intelligence model to detect these depressions using a dataset of confirmed hydrogen-emitting SCDs collected across five countries. Thanks to this diversity in the training data the model can be applied at a global scale having learned to recognize a wide variety of structures associated with hydrogen seepage. To validate its effectiveness the model was tested on two random regions - in Kazakhstan and South Africa - and successfully identified over a thousand new potential hydrogen-emitting depressions. With an average precision of 95 % this tool offers a fast and reliable way to map natural hydrogen seepage zones helping guide future exploration efforts worldwide.

Greenhouse gas anthropogenic emissions have triggered global warming with increasingly alarming consequences motivating the development of carbon-free energy systems. Hydrogen is proposed as an environmentally benign energy vector to implement this strategy but safe and efficient large-scale hydrogen storage technologies are still lacking to develop a competitive Hydrogen economy. LOHC (Liquid Organic Hydrogen Carrier) improves the storage and handling of hydrogen by covalently binding it to a liquid organic framework through catalytic exothermic hydrogenation and endothermic dehydrogenation reactions. LOHCs are oil-like materials that are compatible with the current oil and gas infrastructures. Nevertheless their high dehydrogenation enthalpy platinoid-based catalysts and thermal stability are bottlenecks to the emergence of this technology. In this review hydrogen storage technologies and in particular LOHC are presented. Moreover potential reactivities to design innovative LOHC are discussed.

This article proposes a novel open-circuit switch fault diagnosis method (FDM) for a three-level interleaved buck converter (TLIBC) in a hydrogen production system based on the water electrolysis process. The control algorithm is suitably modified to ensure the same hydrogen production despite the fault. The TLIBC enables the interfacing of the power source (i.e. low-carbon energy sources) and electrolyzer while driving the hydrogen production of the system in terms of current or voltage. On one hand the TLIBC can guarantee a continuity of operation in case of power switch failures because of its interleaved architecture. On the other hand the appearance of a power switch failure may lead to a loss of performance. Therefore it is crucial to accurately locate the failure in the TLIBC and implement a fault-tolerant control strategy for performance purposes. The proposed FDM relies on the comparison of the shape of the input current and the pulse width modulation (PWM) gate signal of each power switch. Finally an experimental test bench of the hydrogen production system is designed and realized to evaluate the performance of the developed FDM and fault-tolerant control strategy for TLIBC during post-fault operation. It is implemented with a real-time control based on a MicroLabBox dSPACE (dSPACE Paderborn Germany) platform combined with a TI C2000 microcontroller. The obtained simulation and experimental results demonstrate that the proposed FDM can detect open-circuit switch failures in one switching period and reconfigure the control law accordingly to ensure the same current is delivered before the failure.