France

Methane pyrolysis is a transitional technology for environmentally benign hydrogen production with zero greenhouse gas emissions especially when concentrated solar energy is the heating source for supplying high-temperature process heat. This study is focused on solar methane pyrolysis as an attractive decarbonization process to produce both hydrogen gas and solid carbon with zero CO2 emissions. Direct normal irradiance (DNI) variations arising from inherent solar resource variability (clouds fog day-night cycle etc.) generally hinder continuity and stability of the solar process. Therefore a novel hybrid solar/electric reactor was designed at PROMES-CNRS laboratory to cope with DNI variations. Such a design features electric heating when the DNI is low and can potentially boost the thermochemical performance of the process when coupled solar/electric heating is applied thanks to an enlarged heated zone. Computational fluid dynamics (CFD) simulations through ANSYS Fluent were performed to investigate the performance of this reactor under different operating conditions. More particularly the influence of various process parameters including temperature gas residence time methane dilution and hybridization on the methane conversion was assessed. The model combined fluid flow hydrodynamics and heat and mass transfer coupled with gas-phase pyrolysis reactions. Increasing the heating temperature was found to boost methane conversion (91% at 1473 K against ~100% at 1573 K for a coupled solar-electric heating). The increase of inlet gas flow rate Q0 lowered methane conversion since it affected the gas space-time (91% at Q0 = 0.42 NL/min vs. 67% at Q0 = 0.84 NL/min). A coupled heating also resulted in significantly better performance than with only electric heating because it broadened the hot zone (91% vs. 75% methane conversion for coupled heating and only electric heating respectively). The model was further validated with experimental results of methane pyrolysis. This study demonstrates the potential of the hybrid reactor for solar-driven methane pyrolysis as a promising route toward clean hydrogen and carbon production and further highlights the role of key parameters to improve the process performance.

The environmental and societal challenges of our contemporary society are leading us to reconsider our approaches to vehicle design. The aim of this article is to provide the reader with the essential knowledge needed to responsibly design a vehicle equipped with a hydrogen fuel cell system. Two pivotal aspects of hydrogen-electric powertrain eco-design are examined. First the global warming potential is assessed for both PEMFC systems and Type IV hydrogen tanks accounting for material extraction production and end-of-life considerations. The usage phase was omitted from the study in order to facilitate data adaptation for each type of use. PEMFC exhibits a global warming potential of about 29.2 kgCO2eq/kW while the tank records 12.4 kgCO2eq/kWh with transportation factors considered. Secondly the societal and governmental impacts are scrutinized with the carbon-intensive hydrogen tank emerging as having the most significant societal and governmental risks. In fact on a scale of 1–5 with 5 representing the highest level of risk the PEMFC system has a societal impact and governance risk of 2.98. The Type IV tank has a societal impact and governance risk of 3.31. Although uncertainties persist regarding the results presented in this study the values obtained provide an overview of the societal and governmental impacts of the hydrogen ecosystem in the transportation sector. The next step will be to compare for the same usage which solution between hydrogen-electric and 100% battery is more respectful of humans and the environment.

This article aims to develop a proton exchange membrane (PEM) electrolyzer emulator. This emulator is realized through an equivalent electrical scheme. It allows taking into consideration the dynamic operation of PEM electrolyzers which is generally neglected in the literature. PEM electrolyzer dynamics are reproduced by the use of supercapacitors due to the high value of the equivalent double-layer capacitance value. Steady-state and dynamics operations are investigated in this work. The design criteria are addressed. The PEM electrolyzer emulator is validated by using a 400-W commercial PEM electrolyzer. This emulator is conceived to test new DC-DC converters to supply the PEM ELs and their control as well avoiding the risk to damage a real electrolyzer for experiment purposes. The proposed approach is valid both for a single cell and for the whole stack emulation.

Numerical results are presented from two direct numerical simulations (DNS) where a moderate hydrogen leakage is modeled in a typical two-vented fuel cell configuration. The study mimics one of the experimental investigations carried out on the 1 m3 enclosure with a leak flow rate of 10.4 Nl.min−1 [1]. The injection dimensionless Richardson number is at the order of unity and thus characterizes a plume flow which becomes turbulent due to gravitational accelerations. Two large exterior regions are added to the computational domain to model correctly the exchange between the in/out flows at both vents and the outer environment. Two meshes are used in this study; a first consisting of 250 million cells while the second has 2 billion cells to ensure the fine DNS resolution at the level of Kolmogorov and Batchelor length scales. The high performance computation (HPC) platform TRUST is employed where the computational domain is distributed up to 5.104 central processing unit (CPU) cores. A detailed description of the flow structure and the hydrogen dispersion is provided where the sharp effect of the cross-flow on the plume is analyzed. Comparisons versus the experimental measurements show a very good agreement where both the bi-layer Linden regime and the maximal concentration in the top homogeneous layer are correctly reproduced by the DNS. This result is extremely important and breaks the limitations shown previously with statistical RANS approaches and LES models. This study can be considered as a good candidate for any further improvements of the theoretical industrial plume models in general and for the estimation of the non-constant entrainment coefficient in particular.

In the framework of the HYTUNNEL-CS European project sponsored by FCH-JU a set of preliminary tests were conducted in a real tunnel in France. These tests are devoted to safety of hydrogen-fueled vehicles having a compressed gas storage and Temperature Pressure Release Device (TPRD). The goal of the study is to develop recommendations for Regulations Codes and Standards (RCS) for inherently safer use of hydrogen vehicles in enclosed transportation systems. Two scenarios were investigated (a) jet fire evolution following the activation of TPRD due to conventional fuel car fire and (b) explosion of compressed hydrogen tank. The obtained experimental data are systematically compared to existing engineering correlations. The results will be used for benchmarking studies using CFD codes. The hydrogen pressure range in these preliminary tests has been lowered down to 20MPa in order to verify the capability of various large-scale measurement techniques before scaling up to 70 MPa the subject of the second experimental campaign.

Non-energy use of natural gas is gaining importance. Gas used for 183 million tons annual ammonia production represents 4% of total global gas supply. 1.5-degree pathways estimate an ammonia demand growth of 3–4-fold until 2050 as new markets in hydrogen transport shipping and power generation emerge. Ammonia production from hydrogen produced via water electrolysis with renewable power (green ammonia) and from natural gas with CO2 storage (blue ammonia) is gaining attention due to the potential role of ammonia in decarbonizing energy value chains and aiding nations in achieving their net-zero targets. This study assesses the technical and economic viability of different routes of ammonia production with an emphasis on a systems level perspective and related process integration. Additional cost reductions may be driven by optimum sizing of renewable power capacity reducing losses in the value chain technology learning and scale-up reducing risk and a lower cost of capital. Developing certification and standards will be necessary to ascertain the extent of greenhouse gas emissions throughout the supply chain as well as improving the enabling conditions including innovative finance and de-risking for facilitating international trade market creation and large-scale project development.

A thermodynamic combustion model developed in AVL BOOST software was used in order to evaluate the pollutant emissions performance and efficiency parameters of a spark ignition engine Renault K7M-710 fueled with compressed natural gas hydrogen and blends of compressed natural gas and hydrogen (hythane). Multiple research studies have concluded that for the near future hythane could be the most promising alternative fuel because it has the advantages of both its components. In our previous work the model was validated for the performance and efficiency parameters by comparison of simulation results with experimental data acquired when the engine was fueled with gasoline. In this work the model was improved and can predict the values of pollutant emissions when the engine is running with the studied alternative fuels. As the percentage of hydrogen in hythane is increased the power of the engine rises the brake specific fuel consumption carbon dioxide carbon monoxide and total unburned hydrocarbon emissions decrease while nitrogen oxides increase. The values of peak fire pressure maximum pressure derivative and peak fire temperature in cycle are higher leading to an increased probability of knock occurrence. To avoid this phenomenon an optimum correlation between the natural gas-hydrogen blend the air-fuel ratio the spark advance and the engine operating condition needs to be found.

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.

Liquid hydrogen (LH2) compared to compressed gaseous hydrogen offers advantages for large-scale transport and storage of hydrogen with higher densities. Although the gas industry has good experience with LH2 only little experience is available for the new applications of LH2 as an energy carrier. Therefore the European FCH JU funded project PRESLHY conducted pre-normative research for the safe use of cryogenic LH2 in non-industrial settings. The central research consisted of a broad experimental program combined with analytical work modelling and simulations belonging to the three key phenomena of the accident chain: release and mixing ignition and combustion. The presented results improve the general understanding of the behavior of LH2 in accidents and provide some design guidelines and engineering tools for safer use of LH2. Recommendations for improvement of current international standards are derived.

The IEA produced this dataset as part of efforts to track advances in low-carbon hydrogen technology. It covers all projects commissioned worldwide since 2000 to produce hydrogen for energy or climate-change-mitigation purposes. It includes projects which their objective is either to reduce emissions associated with producing hydrogen for existing applications or to use hydrogen as an energy carrier or industrial feedstock in new applications that have the potential to be a low-carbon technology. Projects in planning or construction are also covered.

Link to Download Database from IEA Website

The main objective of the article is to provide a thorough review of currently used AC-DC converters for alkaline and proton exchange membrane (PEM) electrolyzers in power grid or wind energy conversion systems. Based on the current literature this article aims at emphasizing the advantages and drawbacks of AC-DC converters mainly based on thyristor rectifier bridges and chopper-rectifiers. The analysis is mainly focused on the current issues for these converters in terms of specific energy consumption current ripple reliability efficiency and power quality. From this analysis it is shown that thyristors-based rectifiers are particularly fit for high-power applications but require the use of active and passive filters to enhance the power quality. By comparison the association combination of the chopper-rectifier can avoid the use of bulky active and passive filters since it can improve power quality. However the use of a basic chopper (i.e. buck converter) presents several disadvantages from the reliability energy efficiency voltage ratio and current ripple point of view. For this reason new emerging DC-DC converters must be employed to meet these important issues according to the availability of new power switching devices. Finally based on the authors’ experience in power conversion for PEM electrolyzers a discussion is provided regarding the future challenges that must face power electronics for green hydrogen production based on renewable energy sources.

Hydrogen has been identified as a very promising vector for energy storage especially for heavy mobility applications. For this reason France is making significant investments in this field and use cases need to be evaluated as they are sprouting. In this paper the relevance of H2 in two storage applications is studied: a domestic renewable electricity production system connected to the grid and a collective hydrogen production for the daily bus refill. The investigation consists of the sizing of the system and then the evaluation of its performance according to several criteria depending on case. Optimizations are made using Bayesian and gradient-based methods. Several variations around a central case are explored for both cases to give insights on the impact of the different parameters (location pricing objective etc.) on the performance of the system.Our results show that domestic power-to-power applications (case 1) do not seem to be competitive with electrochemical storage. Meanwhile without any subsidies or incentives such configuration does not allow prosumers to save money (+16% spendings compared to non-equipped dwelling). It remains interesting when self-sufficiency is the main objective (up to 68% of energy is not exchanged). The power-to-gas application (case 2 central case) with a direct use of hydrogen for mobility seems to be more relevant according to our case study we could reach a production cost of green H2 around 5 €/kg similar to the 3–10 $/kg found in literature for 182 houses involved. In both cases H2 follows a yearly cycle charging in summer and discharging in winter (long term storage) due to low conversion efficiency.

The STOPIL-H2 project supported by the French Geodenergies research consortium aims to design a demonstrator for underground hydrogen storage in cavern EZ53 of the Etrez gas storage (France) operated by Storengy. Two types of tests are planned in this cavern: a tightness test with nitrogen and hydrogen then a cycling test during which the upper part of the cavern (approximately 200 m3) will be filled with hydrogen during 6 to 9 months. In this paper the PRA for the cycling test is presented comprising the identification of the major hazards and the proposed prevention and protection measures. The implemented methodology involves the following steps: data mining from the description of the project; analysis of lessons learned from accidents that occurred in underground gas storage and subface facilities; identification of the potential hazards pertaining to the storage process; analysis of external potential aggressors. Resulting as one of the outcomes of the PRA major accidental scenarios are presented and classified according to concerned storage operation phases as well as determined preventive or protective barriers able to prevent their occurrence of mitigate their consequences.

The environmental impact of CO2 emissions is widely acknowledged making the development of alternative propulsion systems a priority. Hydrogen is a potential candidate to replace fossil fuels for transport applications with three technologies considered for the onboard storage of hydrogen: storage in the form of a compressed gas storage as a cryogenic liquid and storage as a solid. These technologies are now competing to meet the requirements of vehicle manufacturers; each has its own unique challenges that must be understood to direct future research and development efforts. This paper reviews technological developments for Hydrogen Storage Vessel (HSV) designs including their technical performance manufacturing costs safety and environmental impact. More specifically an up-to-date review of fiber-reinforced polymer composite HSVs was explored including the end-of-life recycling options. A review of current numerical models for HSVs was conducted including the use of artificial intelligence techniques to assess the performance of composite HSVs leading to more sophisticated designs for achieving a more sustainable future.

Rising climate change ambitions require large-scale clean hydrogen production in the near term. “Blue” hydrogen from conventional steam methane reforming (SMR) with pre-combustion CO2 capture can fulfil this role. This study therefore presents techno-economic assessments of a range of SMR process configurations to minimize hydrogen production costs. Results showed that pre-combustion capture can avoid up to 80% of CO2 emissions cheaply at 35 €/ton but the final 20% of CO2 capture is much more expensive at a marginal CO2 avoidance cost around 150 €/ton. Thus post-combustion CO2 capture should be a better solution for avoiding the final 20% of CO2. Furthermore an advanced heat integration scheme that recovers most of the steam condensation enthalpy before the CO2 capture unit can reduce hydrogen production costs by about 6%. Two hybrid hydrogen production options were also assessed. First a “blue-green” hydrogen plant that uses clean electricity to heat the reformer achieved similar hydrogen production costs to the pure blue configuration. Second a “blue turquoise” configuration that replaces the pre-reformer with molten salt pyrolysis for converting higher hydrocarbons to a pure carbon product can significantly reduce costs if carbon has a similar value to hydrogen. In conclusion conventional pre-combustion CO2 capture from SMR is confirmed as a good solution for kickstarting the hydrogen economy and it can be tailored to various market conditions with respect to CO2 electricity and pure carbon prices.

The EU’s hydrogen strategy consists of studying the potential for renewable hydrogen to help decarbonize the EU in a cost-effective way. Today hydrogen accounts for less than 2% of Europe’s energy consumption. It is primarily used to produce chemical products. However 96% of this hydrogen production is through natural gas leading to significant amounts of CO2 emissions. In this paper we investigated PV electrolysis H2 gas (noted H2(g)) production for mapping this resource at Europe’s scale. The Cordex/Copernicus RCPs scenarios allow for evaluating the impact of climate changes on the H2 -produced mass and the equivalent energy according to both extreme RCPs scenarios. New linear regressions are investigated to study the great dependence in H2(g) produced masses (kg·yr−1 ) and equivalent energies (MWh·yr−1 ) for European countries. Computational scenarios are investigated from a reference year (2005) to the end of the century (2100) by steps of 5 years. According to RCPs 2.6 (favorable)/8.5 (extreme) 31.7% and 77.4% of Europe’s area presents a decrease of H2(g)-produced masses between 2005 and 2100. For the unfavorable scenario (8.5) only a few regions located in the northeast of France Germany Austria Romania Bulgaria and Greece present a positive balance in H2(g) production for supplying remote houses or smart grids in electricity and heat energy.

Solid oxide electrolysis cell is the leading technology for production of green hydrogen by high temperature electrolysis. However optimization of existing reference materials constituting the cell and development of innovative materials remain critical for solid oxide electrolysis cell. In particular they are key to reach performance and durability targets compatible with a commercialization for the three main markets identified as follows: large-scale H2 production Power-to-X and Power-to-Power. This short review summarizes the latest progress in research and development of alternative and innovative materials for solid oxide electrolysis cells with a main focus on cathode-supported cell materials. A brief description of the layers constituting the solid oxide electrolysis cell is provided with the associated current state-of-the-art materials. A further emphasis on the most promising alternative and innovative materials for each layer follows based on the major aspects from an industrial perspective to reach a competitive hydrogen production cost for the main targeted markets: performance durability scaling up/manufacturing ability and operational flexibility.

Underground Hydrogen storage (UHS) is a promising technology for safe storage of large quantities of hydrogen in daily to seasonal cycles depending on the consumption requirements. The development of UHS requires anticipating hydrogen behavior to prevent any unexpected economic or environmental impact. An open question is the hydrogen reactivity in underground porous media storages. Indeed there is no consensus on the effects or lack of geochemical reactions in UHS operations because of the strong coupling with the activity of microbes using hydrogen as electron donor during anaerobic reduction reactions. In this work we apply different geochemical models to abiotic conditions or including the catalytic effect of bacterial activity in methanogenesis acetogenesis and sulfate-reduction reactions. The models are applied to Lobodice town gas storage (Czech Republic) where a conversion of hydrogen to methane was measured during seasonal gas storage. Under abiotic conditions no reaction is simulated. When the classical thermodynamic approach for aqueous redox reactions is applied the simulated reactivity of hydrogen is too high. The proper way to simulate hydrogen reactivity must include a description of the kinetics of the aqueous redox reactions. Two models are applied to simulate the reactions of hydrogen observed at Lobodice gas storage. One modeling the microbial activity by applying energy threshold limitations and another where microbial activity follows a Monod-type rate law. After successfully calibrating the bio-geochemical models for hydrogen reactivity on existing gas storage data and constraining the conditions where microbial activity will inhibit or enhance hydrogen reactivity we now have a higher confidence in assessing the hydrogen reactivity in future UHS in aquifers or depleted reservoirs.

Accurate estimation of mass flow rate and release conditions is important for the design of dispersion and combustion experiments for the subsequent validation of CFD codes/models for consequence assessment analysis within related risk assessment studies and for associated Regulation Codes and Standards development. This work focuses on the modelling of the discharge phase of the recent large scale LH2 release and dispersion experiments performed by HSE within the framework of PRESLHY project. The experimental conditions covered sub-cooled liquid stagnation conditions at two pressures (2 and 6 bara) and 3 release nozzle diameters (1 ½ and ¼ inches). The simulations were performed using a 1d engineering tool which accounts for discharge line effects due to friction extra resistance due to fittings and area change. The engineering tool uses the Possible Impossible Flow (PIF) algorithm for choked flow calculations and the Helmholtz Free Energy (HFE) EoS formulation. Three different phase distribution models were applied. The predictions are compared against measured and derived data from the experiments and recommendations are given both regarding engineering tool applicability and future experimental design.

The share of electrical energy from renewable sources has increased considerably in recent years in an attempt to reduce greenhouse gas emissions. To mitigate the uncertainties of these sources and to balance energy production with consumption an energy storage system (ESS) based on water electrolysis to produce hydrogen is studied. It can be applied to AC microgrids where several renewable energy sources and several loads may be connected which is the focus of the study. When excess electricity production is converted into hydrogen via water electrolysis low DC voltages and high currents are applied which needs specific power converters. The use of a three-phase buck-type current source converter in a single conversion stage allows for an adjustable DC voltage to be obtained at the terminals of the electrolyzer from a three-phase AC microgrid. The voltage control is preferred to the current control in order to improve the durability of the system. The classical control of the buck-type rectifier is generally done using two loops that correspond only to the control of its output variables. The lack of control of the input variables may generate oscillations of the grid current. Our contribution in this article is to propose a new control for the buck-type rectifier that controls both the input and output variables of the converter to avoid these grid current oscillations without the use of active damping methods. The suggested control method is based on an approach using the flatness properties of differential systems: it ensures the large-signal stability of the converter. The proposed control shows better results than the classical control especially in oscillation mitigation and dynamic performances with respect to the rejection of disturbances caused by a load step.

To face the intensive use of natural gas and other fossil fuels to generate hydrogen water electrolysis based on renewable energy sources (RES) seems to be a viable solution. Due to their fast response times and high efficiency proton exchange membrane electrolyzer (PEM EL) is the most suitable technology for long-term energy storage combined with RES. Like fuel cells the development of fit DC-DC converters is mandatory to interface the EL to the DC grid. Given that PEM EL operating voltages are quite low and to meet requirements in terms of output current ripples new emerging interleaved DC-DC converter topologies seem to be the best candidates. In this work a three-level interleaved DC-DC buck converter has been chosen to supply a PEM EL from a DC grid. Therefore the main objective of this paper is to develop a suitable control strategy of this interleaved topology connected to a PEM EL emulator. To design the control strategy investigations have been carried out on energy efficiency hydrogen flow rate and specific energy consumption. The obtained experimental results validate the performance of the converter in protecting the PEM EL during transient operations while guaranteeing correct specific energy consumption.

Hydrogen is the cleanest fuel available because its combustion product is water. The internal combustion engine can in principle and without significant modifications run on hydrogen to produce mechanical energy. Regarding the technological solution leading to compact engines a question to ask is the following: Can combustion engine systems be lubricated with hydrogen? In general since many applications such as in turbomachines is it possible to use the surrounding gas as a lubricant? In this paper journal bearings global parameters are calculated and compared for steady state and dynamic conditions for different gas constituents such as air pentafluoropropane helium and hydrogen. Such a bearing may be promising as an ecological alternative to liquid lubrication.

The use of hydrogen as energy carrier in a low emission microturbine could be an interesting option for renewable energy storage distributed generation and combined heat & power. However the hydrogen using in gas turbine is limited by the NOx emissions and the difficulty to operate safely. CFD simulations represent a powerful and mature tool to perform detailed 3-D investigation for the development of a prototype before carrying out an experimental analysis. This paper describes the CFD supported redesign of the Turbec T100 microturbine combustion chamber natural gas-fired to allow the operation on 100% hydrogen.

The aim of this paper is the design and implementation of an advanced model predictive control (MPC) strategy for the management of a wind–solar microgrid (MG) both in the islanded and grid-connected modes. The MG includes energy storage systems (ESSs) and interacts with external hydrogen and electricity consumers as an extra feature. The system participates in two different electricity markets i.e. the daily and real-time markets characterized by different time-scales. Thus a high-layer control (HLC) and a low-layer control (LLC) are developed for the daily market and the real-time market respectively. The sporadic characteristics of renewable energy sources and the variations in load demand are also briefly discussed by proposing a controller based on the stochastic MPC approach. Numerical simulations with real wind and solar generation profiles and spot prices show that the proposed controller optimally manages the ESSs even when there is a deviation between the predicted scenario determined at the HLC and the real-time one managed by the LLC. Finally the strategy is tested on a lab-scale MG set up at Khalifa University Abu Dhabi UAE.

Hydrogen storage is a key enabling technology for the extensive use of hydrogen as energy carrier. This is particularly true in the widespread introduction of hydrogen in car transportation. Indeed one of the greatest technological barriers for such development is an efficient and safe storage method. So in this tutorial review the existing hydrogen storage technologies are described with a special emphasis on hydrogen storage in hydrogen cars: the current and the ongoing solutions. A particular focus is given on solid storage and some of the recent advances on plasma hydrogen ion implantation which should allow not only the preparation of metal hydrides but also the imagination of a new refluing circuit. From hydrogen discovery to its use as an energy vector in cars this review wants to be as exhaustive as possible introducing the basics of hydrogen storage and discussing the experimental practicalities of car hydrogen fuel. It wants to serve as a guide for anyone wanting to undertake such a technology and to equip the reader with an advanced knowledge on hydrogen storage and hydrogen storage in hydrogen cars to stimulate further researches and yet more innovative applications for this highly interesting field.