Publications

The European gas industry has argued that gas can be a bridging fuel in the transition to decarbonised energy markets because of the advantages of switching from coal to gas and the role of gas in backing up intermittent renewable power generation. While this remains a logical approach for some countries in others it has proved either not relevant or generally unsuccessful in gaining acceptance with either policymakers or the environmental community. Policy decisions will be taken in the next 5-10 years which will irreversibly impact the future of gas in the period 2030-50. A paradigm shift in commercial time horizons and gas value chain cooperation will be necessary for the industry to embrace decarbonisation technologies (such as carbon capture and storage) which will eventually be necessary if gas is to prolong its future in European energy markets. To ensure a post-2030 future in European energy balances the gas community will be obliged to adopt a new message: `Gas can Decarbonise’ (and remain competitive with other low/zero carbon energy supplies). It will need to back up this message with a strategy which will lead to the decarbonisation of methane starting no later than 2030. Failure to do so will be to accept a future of decline albeit on a scale of decades and to risk that by the time the community engages with decarbonisation non-methane policy options will have been adopted which will make that decline irreversible.

Direct Numerical Simulations (DNS) are performed to investigate the process of spontaneous ignition of hydrogen flames at laminar turbulent adiabatic and non-adiabatic conditions. Mixtures of hydrogen and vitiated air at temperatures representing gas-turbine reheat combustion are considered. Adiabatic spontaneous ignition processes are investigated first providing a quantitative characterization of stable and unstable flames. Results indicate that in hydrogen reheat combustion compressibility effects play a key role in flame stability and that unstable ignition and combustion are consistently encountered for reactant temperatures close to the mixture’s characteristic crossover temperature. Furthermore it is also found that the characterization of the adiabatic processes is also valid in the presence of non-adiabaticity due to wall heat-loss. Finally a quantitative characterization of the instantaneous fuel consumption rate within the reaction front is obtained and of its ability at auto-ignitive conditions to advance against the approaching turbulent flow of the reactants for a range of different turbulence intensities temperatures and pressure levels.

A consortiumcomprising Cadent Gas Health and Safety Executive – Science Division ITMPower Keele University Northern Gas Networks and Progressive Energy is undertaking the second phase of the research project HyDeploy. The project the first two phase ofwhich are funded under the UK Network Innovation Competition scheme aims to demonstrate that natural gas containing levels of hydrogen beyond the upper limit set out in Schedule 3 of in the Gas Safety (Management) Regulations (GSMR) can be distributed and utilised safely and efficiently in the UK gas distribution networks.<br/>The first phase of the HyDeploy project concludes with a 10-month field trial in which hydrogen will be injected into part of a private gas distribution system owned and operated by Keele University.<br/>The second phase of the HyDeploy project (HyDeploy2) continues on from the work of the first phase and is scheduled to conclude with two 12-month field trials in which hydrogen will be injected into public gas networks owned and operated by Northern Gas Networks and Cadent Gas.<br/>Dave Lander Consulting Limited is providing technical support to the HyDeploy project and this report presents the results of Quantified Risk Assessment (QRA) for the proposed field trial of hydrogen injection into part of a gas distribution system owned and operated by Northern Gas Networks (NGN) near the town of Winlaton in Gateshead Tyne and Wear. The QRA is intended to support an application by NGN for exemption from the legal requirement to only convey gas that is compliant with the requirements of Schedule 3 of the GSMR. The QRA estimates the risk to persons within the trial area affected by the proposed injection. A similar QRA1 was developed for the original HyDeploy field trial at Keele University.<br/>Click on the supplement tab to see the other documents from this report

Hydrogen is an explosive gas which could create extremely hazardous conditions when released into an enclosure. Full-scale experiments of hydrogen release and dispersion in the confined space were conducted. The experiments were performed for hydrogen release outflow of 63 × 10−3 m3/s through a single nozzle and multi-point release way optionally. It was found that the hydrogen dispersion in an enclosure strongly depends on the gas release way. Significantly higher hydrogen stratification is observed in a single nozzle release than in the case of the multi-point release when the gas concentration becomes more uniform in the entire enclosure volume. The experimental results were confirmed on the basis of Froud number analysis. The CFD simulations realized with the FDS code by NIST allowed visualization of the experimental hydrogen dispersion phenomenon and confirmed that the varied distribution of hydrogen did not affect the effectiveness of the accidental mechanical ventilation system applied in the tested room.

Hydrogen embrittlement can cause catastrophic failure of high strength alloys yet determining localised hydrogen in the microstructure is analytically challenging. NanoSIMS is one of the few techniques that can map hydrogen and deuterium in metal samples at microstructurally relevant length scales. Therefore it is essential to understand the artefacts and determine the optimum methodology for its reliable detection. An experimental methodology/protocol for NanoSIMS analysis of deuterium (as a proxy for hydrogen) has been established uncovering unreported artefacts and a new approach is presented to minimise these artefacts in mapping hydrogen and deuterium in alloys. This method was used to map deuterium distributions in electrochemically charged austenitic stainless steel and precipitation hardened nickel-based alloys. Residual deuterium contamination was detected in the analysis chamber as a result of deuterium outgassing from the samples and the impact of this deuterium contamination was assessed by a series of NanoSIMS experiments. A new analysis protocol was developed that involves mapping deuterium in the passive oxide layer thus mitigating beam damage effects that may prevent the detection of localised deuterium signals when the surface is highly deuterated.

Preventing humanity from serious impact of climate crisis requires carbon neutrality across all economic sectors including steel industry. Although fossil-free steelmaking routes receiving increasing attention fundamental process aspects especially approaches towards the improvement of efficiency and flexibility are so far not comprehensively studied. In this paper optimized process concepts allowing for a gradual transition towards fossil-free steelmaking based on the coupling of direct reduction process electric arc furnace and electrolysis are presented. Both a high-temperature and low-temperature electrolysis were modeled and possibilities for the integration into existing infrastructure are discussed. Various schemes for heat integration especially when using high-temperature electrolysis are highlighted and quantified. It is demonstrated that the considered direct reduction-based process concepts allow for a high degree of flexibility in terms of feed gas composition when partially using natural gas as a bridge technology. This allows for an implementation in the near future as well as the possibility of supplying power grid services in a renewable energy system. Furthermore it is shown that an emission reduction potential of up to 97.8% can be achieved with a hydrogen-based process route and 99% with a syngas-based process route respectively provided that renewable electricity is used.

Wind and solar energies present a time and space disparity that generally leads to a mismatch between the demand and the supply. To harvest their maximum potentials one of the main challenges is the storage and transport of these energies. This challenge can be tackled by electrofuels such as hydrogen methane and methanol. They offer three main advantages: compatibility with existing distribution networks or technologies of conversion economical storage solution for high capacity and ability to couple sectors (i.e. electricity to transport to heat or to industry). However the level of contribution of electric-energy carriers is unknown. To assess their role in the future we used whole-energy system modelling (EnergyScope Typical Days) to study the case of Belgium in 2050. This model is multi-energy and multi-sector. It optimises the design of the overall system to minimise its costs and emissions. Such a model relies on many parameters (e.g. price of natural gas efficiency of heat pump) to represent as closely as possible the future energy system. However these parameters can be highly uncertain especially for long-term planning. Consequently this work uses the polynomial chaos expansion method to integrate a global sensitivity analysis in order to highlight the influence of the parameters on the total cost of the system. The outcome of this analysis points out that compared to the deterministic cost-optimum situation the system cost accounting for uncertainties becomes higher (+17%) and twice more uncertain at carbon neutrality and that electrofuels are a major contribution to the uncertainty (up to 53% in the variation of the costs) due to their importance in the energy system and their high uncertainties their higher price and uncertainty.

Preliminary research suggests domestic carbon monoxide detectors with an electrochemical sensor are approximately 10 -20% sensitive to hydrogen atmospheres in their factory configuration. That is the display on a carbon monoxide detector would give a carbon monoxide reading of approximately 10-20% of the concentration of hydrogen it is exposed to. Current British standards require detectors to sound an alarm within three minutes when subjected to a continuous concentration of ≥ 300 ppm CO. This would equate to a concentration of 1500-3000 ppm hydrogen in air or approximately 3.75 – 7% %LEL. The current evacuation criteria for a natural gas leak in a domestic property is 20 %LEL indicating that standard carbon monoxide detectors could be used as cheap and reliable early warning systems for hydrogen leaks. Given the wide use of carbon monoxide detectors and the affordability of the devices the use of carbon monoxide detectors for hydrogen detection is of particular interest as the UK drives towards energy decarbonisation. Experiments to determine the exact sensitivity of a range of the most common domestic carbon monoxide detectors have been completed by DNV Spadeadam Research & Testing. Determining the effects of repeated exposure to varying concentrations of hydrogen in air on the sensitivity of electrochemical sensors allows recommendations to be made on their adoption as hydrogen detectors. Changing the catalysts used within the electrochemical cell would improve the sensitivity to hydrogen however simply calibrating the sensor to report a concentration of hydrogen rather than carbon monoxide would represent no additional costs to manufacturers. Having determined the suitability of such sensors at an early stage; the technology can then be linked with other technological developments required for the change to hydrogen for domestic heating (e.g. change in metering equipment and appliances). This report finds that from five simple and widely available carbon monoxide detectors the lowest sensitivity to hydrogen measured at the concentration required to sound an alarm within three minutes was approximately 10%. It was also discovered that as the hydrogen concentration was increased over the range tested the sensitivity to hydrogen also increased. It is proposed that coupling these devices with other elements of the domestic gas system would allow actions such as remote meter isolation or automatic warning signals sent to response services would provide a reliable and inherently safe system for protecting occupants as gas networks transition to net-zero greenhouse gas emissions. In this respect it is noted that wireless linking of smoke and heat detectors for domestic application is already widely available in low-cost devices. This could be extended to CO detectors adapted for hydrogen use.

Bilayer Mg/Ti (200 nm) thin films were successfully prepared by using D.C. magnetron sputtering unit. These films were vacuum annealed at 573 K temperature for one hour to obtain homogeneous and intermixed structure of bilayer. Hydrogenation of these thin film structures was made at different hydrogen pressure (15 30 & 45 psi) for 30 min to visualize the effect of hydrogen on film structure. The UV–Vis absorption spectra I-V characteristics and Raman spectroscopy were carried out to study the effect of hydrogen on optical electrical and structural properties of Mg/Ti bilayer thin films. The annealed thin film represents the semiconductor nature with the conductivity of the order of 10-5 Ώ⁻¹-m⁻¹ and it decreases as hydrogen pressure increases. The nonlinear dependence of resistivity on hydrogen pressure reveals inhomogeneous distribution of hydrogen in the thin film. Raman spectroscopy confirmed the presence of hydrogen in thin film where the intensity of peaks was found to be decreased with hydrogen pressure.

Electrochemical energy storage is a key enabling technology for further integration of renewables sources. Redox flow batteries(RFBs) are promising candidates for such applications as a result of their durability efficiency and fast response. However deployment of existing RFBs is hindered by the relatively high cost of the (typically vanadium-based) electrolyte. Manganese is an earth-abundant and inexpensive element that is widely used in disposable alkaline batteries. However it has hitherto been little explored for RFBs due to the instability of Mn(III) leading to precipitation of MnO2 via a disproportionation reaction. Here we show that by combining the facile hydrogen negative electrode reaction with electrolytes that suppress Mn(III) disproportionation it is possible to construct a hydrogen/manganese hybrid RFB with high round trip energy efficiency (82%) and high power and energy density (1410 mW cm−2 33 Wh l−1 ) at an estimated 70% cost reduction compared to vanadium redox flow batteries.

This study aims to assess the potential risks of setting up a hydrogen infrastructure in the Netherlands. An integrated risk assessment framework capable of analyzing projects identifying risks and comparing projects is used to identify and analyze the main risks in the upcoming Dutch hydrogen infrastructure project. A time multiplier is added to the framework to develop parameters. The impact of the different risk categories provided by the integrated framework is calculated using the discounted cash flow (DCF) model. Despite resource risks having the highest impact scope risks are shown to be the most prominent in the hydrogen infrastructure project. To present the DCF model results a risk assessment matrix is constructed. Compared to the conventional Risk Assessment Matrix (RAM) used to present project risks this matrix presents additional information in terms of the internal rate of return and risk specifics.

Fuel cells as clean power sources are very attractive for the maritime sector which is committed to sustainability and reducing greenhouse gas and atmospheric pollutant emissions from ships. This paper presents a technological review on fuel cell power systems for maritime applications from the past two decades. The available fuels including hydrogen ammonia renewable methane and methanol for fuel cells under the context of sustainable maritime transportation and their pre-processing technologies are analyzed. Proton exchange membrane molten carbonate and solid oxide fuel cells are found to be the most promising options for maritime applications once energy efficiency power capacity and sensitivity to fuel impurities are considered. The types layouts and characteristics of fuel cell modules are summarized based on the existing applications in particular industrial or residential sectors. The various research and demonstration projects of fuel cell power systems in the maritime industry are reviewed and the challenges with regard to power capacity safety reliability durability operability and costs are analyzed. Currently power capacity costs and lifetime of the fuel cell stack are the primary barriers. Coupling with batteries modularization mass production and optimized operating and control strategies are all important pathways to improve the performance of fuel cell power systems.

The Hy4Heat Safety Assessment has focused on assessing the safe use of hydrogen gas in certain types of domestic properties and buildings. The summary reports (the Precis and the Safety Assessment Conclusions Report) bring together all the findings of the work and should be looked to for context by all readers. The technical reports should be read in conjunction with the summary reports. While the summary reports are made as accessible as possible for general readers the technical reports may be most accessible for readers with a degree of technical subject matter understanding. All of the safety assessment reports have now been reviewed by the HSE.<br/><br/>A comparative risk assessment of natural gas versus hydrogen gas including a quantitative risk assessment; and identification of control measures to reduce risk and manage hydrogen gas safety for a community demonstration.

Turquoise hydrogen is produced from methane cracking a cleaner alternative to steam methane reforming. This study looks at two proposed systems based on solar methane cracking for low-carbon fuel production. The systems utilize different pathways to convert the hydrogen into a suitable form for transportation and utilize the carbon solid by-product. A direct carbon fuel cell is integrated to utilize the carbon and capture the CO2 emissions. The CO2 generated is utilized for fuel production using CO2 hydrogenation or co-electrolysis. An advanced exergetic analysis is conducted on these systems using Aspen plus simulations of the process. The exergetic efficiency waste exergy ratio exergy destruction ratio exergy recoverability ratio environmental effect factor and the exergetic sustainability index were determined for each system and the subsystems. Solar methane cracking was found to have an environmental effect factor of 0.08 and an exergetic sustainability index of 12.27.

The investigation of the various heat management concepts using LH2 requires the development of a modeling environment coupling the cryogenic hydrogen fuel system with turbofan performance. This paper presents a numerical framework to model hydrogen-fueled gas turbine engines with a dedicated heat-management system complemented by an introductory analysis of the impact of using LH2 to precool and intercool in the compression system. The propulsion installations comprise Brayton cycle-based turbofans and first assessments are made on how to use the hydrogen as a heat sink integrated into the compression system. Conceptual tubular compact heat exchanger designs are explored to either precool or intercool the compression system and preheat the fuel to improve the installed performance of the propulsion cycles. The precooler and the intercooler show up to 0.3% improved specific fuel consumption for heat exchanger effectiveness in the range 0.5–0.6 but higher effectiveness designs incur disproportionately higher pressure losses that cancel-out the benefits.

The National Renewable Energy Laboratory’s (NREL) Hydrogen Safety Research and Development (HSR&D) program in collaboration with the University of Maryland’s Systems Risk and Reliability Analysis Laboratory (SyRRA) are working to improve reliability and reduce risk in hydrogen systems. This approach strives to use quantitative data on component leaks and failures together with Prognosis and Health Management (PHM) and Quantitative Risk Assessment (QRA) to identify atrisk components reduce component failures and downtime and predict when components require maintenance. Hydrogen component failures increase facility maintenance cost facility downtime and reduce public acceptance of hydrogen technologies ultimately increasing facility size and cost because of conservative design requirements. Leaks are a predominant failure mode for hydrogen components. However uncertainties in the amount of hydrogen emitted from leaking components and the frequency of those failure events limit the understanding of the risks that they present under real-world operational conditions. NREL has deployed a test fixture the Leak Rate Quantification Apparatus (LRQA) to quantify the mass flow rate of leaking gases from medium and high-pressure components that have failed while in service. Quantitative hydrogen leak rate data from this system could ultimately be used to better inform risk assessment and Regulation Codes and Standards (RCS). Parallel activity explores the use of PHM and QRA techniques to assess and reduce risk thereby improving safety and reliability of hydrogen systems. The results of QRAs could further provide a systematic and science-based foundation for the design and implementation of RCS as in the latest versions of the NFPA 2 code for gaseous hydrogen stations. Alternatively data-driven techniques of PHM could provide new damage diagnosis and health-state prognosis tools. This research will help end users station owners and operators and regulatory bodies move towards risk-informed preventative maintenance versus emergency corrective maintenance reducing cost and improving reliability. Predictive modelling of failures could improve safety and affect RCS requirements such as setback distances at liquid hydrogen fueling sites. The combination of leak rate quantification research PHM and QRA can lead to better informed models enabling data-based decision to be made for hydrogen system safety improvements.

The shipping industry is becoming increasingly aware of its environmental responsibilities in the long-term. In 2018 the International Maritime Organization (IMO) pledged to reduce greenhouse gas (GHG) emissions by at least 50% by the year 2050 as compared with a baseline value from 2008. Ammonia has been regarded as one of the potential carbon-free fuels for ships based on these environmental issues. In this paper we propose four propulsion systems for a 2500 Twenty-foot Equivalent Unit (TEU) container feeder ship. All of the proposed systems are fueled by ammonia; however different power systems are used: main engine generators polymer electrolyte membrane fuel cell (PEMFC) and solid oxide fuel cell (SOFC). Further these systems are compared to the conventional main engine propulsion system that is fueled by heavy fuel oil with a focus on the economic and environmental perspectives. By comparing the conventional and proposed systems it is shown that ammonia can be a carbon-free fuel for ships. Moreover among the proposed systems the SOFC power system is the most eco-friendly alternative (up to 92.1%) even though it requires a high lifecycle cost than the others. Although this study has some limitations and assumptions the results indicate a meaningful approach toward solving GHG problems in the maritime industry.

This work focuses on tests for control reserve of a novel Power-to-Gas-to-Power platform based on proton exchange membrane technologies and on pure oxygen instead of air in the re-electrification process. The technologies are intended as a further option to stabilize the power system therefore helping integrating renewable energy into the power system. The tests are based on the pre-qualification tests used by Swissgrid but are not identical in order to capture the maximum dynamics by the plants. The main characteristics identified are the ramping capabilities of ±8% per unit per second for the electrolyzer system and ±33% per unit per second for the fuel cell system. The ramping capabilities are mainly limited by the underlying processes of polymer electrolyte membrane technologies. Additionally the current and projected round-trip efficiencies for Power-to-Gas-to-Power of 39% in 2025 and 48% in 2040 are derived. Furthermore during the successful tests the usage of oxygen in the present Power-to-Gas and Gas-to-Power processes and its influence on the dynamics and the round-trip efficiency was assessed. In consequence fundamental data on the efficiency and the dynamics of the Power-to-Gas-to-Power technologies is presented. This data can serve as basis for prospective assessments on the suitability of the technologies investigated for frequency control in power systems.

This statutory report provides a comprehensive overview of the UK Government’s progress to date in reducing emissions. It is accompanied by a new Monitoring Framework which details the CCC’s updated approach to tracking real-world progress through a host of new indicators.<br/>This is a pivotal point in the UK’s journey to Net Zero. The UK is one of the few countries with emissions targets in line with the long-term temperature goal of the Paris Agreement. Policy ambition has moved substantially with the publication of the UK’s Net Zero Strategy. Now is the time to deliver the promised action.

One option to decarbonise residential heat in the UK is to convert the existing natural gas networks to deliver hydrogen. We review the technical feasibility of this option using semistructured interviews underpinned by a literature review and we assess the potential economic benefits using the UK MARKAL energy systems model. We conclude that hydrogen can be transported safely in the low-pressure pipes but we identify concerns over the reduced capacity of the system and the much lower linepack storage compared to natural gas. New hydrogen meters and sensors would have to be fitted to every building in a hydrogen conversion program and appliances would have to be converted unless the government was to legislate to make them hydrogen-ready in advance. Converting the gas networks to hydrogen is a lower-cost residential decarbonisation pathway for the UK than those identified previously. The cost-optimal share of hydrogen is sensitive to the conversion cost and to variations in the capital costs of heat pumps and micro-CHP fuel cells. With such small cost differentials between technologies the decision to convert the networks will also depend on non-economic factors including the relative performance of technologies and the willingness of the government to organise a conversion program.

Hydrogen fuel cell vehicles (FCVs) are regarded as a promising solution to the problems of energy security and environmental pollution. However the technology is under development and the hydrogen consumption is uncertain. The quantitative evaluation of life cycle energy consumption pollution emissions of current and future FCVs in China involves complex processes and parameters. Therefore this study addresses Life Cycle Assessment (LCA) of FCV and focuses on the key parameters of FCV production and different hydrogen production methods which include steam methane reforming catalysis decomposition methanol steam reforming electrolysis–photovoltaic (PV) and electrolysis Chinese electricity grid mix (CN). Sensitivity analysis of bipolar plate glider mass power density fuel cell system efficiency and energy control strategy are performed whilst accounting for different assumption scenarios. The results show that all impact assessment indicators will decrease by 28.8– 44.3% under the 2030 positive scenario for the production of FCVs. For cradle-grave FCVs the use of hydrogen from electrolysis operated with photovoltaic power reduces global warming potential (GWP) by almost 76.4% relative to steam methane reforming. By contrast the use of hydrogen from electrolysis operated with the Chinese electricity grid mix results in an increase in GWP of almost 158.3%.

Photocatalysts lead vitally to water purifications and decarbonise environment each by wastewater treatment and hydrogen (H2 ) production as a renewable energy source from waterphotolysis. This work deals with the photocatalytic degradation of ciprofloxacin (CIP) and H2 production by novel silver-nanoparticle (AgNPs) based ternary-nanocomposites of thiolated reducegraphene oxide graphitic carbon nitride (AgNPs-S-rGO2%@g-C3N4 ) material. Herein the optimised balanced ratio of thiolated reduce-graphene oxide in prepared ternary-nanocomposites played matchlessly to enhance activity by increasing the charge carriers’ movements via slowing down charge-recombination ratios. Reduced graphene oxide (rGO) >2 wt.% or < 10 nm. Therefore AgNPs-S-rGO2%@g-C3N4 has 3772.5 µmolg−1 h −1 H2 production which is 6.43-fold higher than g-C3N4 having cyclic stability of 96% even after four consecutive cycles. The proposed mechanism for AgNPs-S-rGO2%@g-C3N4 revealed that the photo-excited electrons in the conduction-band of g-C3N4 react with the adhered water moieties to generate H2 .

Underground hydrogen storage (UHS) has been launched as a catalyst to the low-carbon energy transitions. The limited understanding of the subsurface processes is a major obstacle for rapid and widespread UHS implementation. We use microfluidics to experimentally describe pore-scale multiphase hydrogen flow in an aquifer storage scenario. In a series of drainage-imbibition experiments we report the effect of capillary number on hydrogen saturations displacement/trapping mechanisms dissolution kinetics and contact angle hysteresis. We find that the hydrogen saturation after injection (drainage) increases with increasing capillary number. During hydrogen withdrawal (imbibition) two distinct mechanisms control the displacement and residual trapping – I1 and I2 imbibition mechanisms respectively. Local hydrogen dissolution kinetics show dependency on injection rate and hydrogen cluster size. Dissolved global hydrogen concentration corresponds up to 28 % of reported hydrogen solubility indicating pore-scale non-equilibrium dissolution. Contact angles show hysteresis and vary between 17 and 56°. Our results provide key UHS experimental data to improve understanding of hydrogen multiphase flow behavior.

The European Marine Energy Centre’s (EMEC) ITEG project (Integrating Tidal Energy into the European Grid) funded by Interreg NWE combines a tidal energy and hydrogen production solution to address grid constraints on the island of Eday in Orkney. The project will install a 0.5MW electrolyser at EMEC’s existing hydrogen production plant. EMEC and Risktec collaboratively applied best practice risk assessment and management techniques to assess and manage hydrogen safety. Hazard identification (HAZID) workshops were conducted collaboratively with design engineers through which a comprehensive hazard register was developed. Risktec applied bowtie analysis to each major accident hazard identified from the hazard register via virtual workshop with design engineers. The bowties promoted a structured review of each hazard’s threat and consequence identifying and reviewing the controls in place against good practice standards. The process revealed some recommendations for further improvement and risk reduction exemplifying a systematic management of risks associated with hydrogen hazards to as low as reasonably practicable (ALARP). Hardware based barriers preventing or mitigating loss of control of these hazards were logged as safety critical elements (SCE) and procedural barriers as safety critical activities (SCA). To ensure that all SCEs and SCAs identified through the risk assessment process are managed throughout the facility’s operational lifetime a safety management system is created giving assurance of overall safety management system continued effectiveness. The process enables the demonstration that design risks are managed to ALARP during design and throughout operational lifetime. More importantly enabling ITEG to progress to construction and operation in 2021.

Liquid hydrogen has the potential to form part of the energy strategy in the future due to the need to decarbonise and replace fossil fuels and therefore could see widespread use. Adoption of LH2 means that the associated hazards need to be understood and managed. In recognition of this the European Union Fuel Cells and Hydrogen Joint Undertaking co-funded project PRESLHY undertook prenormative research for the safe use of cryogenic liquid hydrogen in non-industrial settings. Several key scenarios were identified as knowledge gaps and both theoretical and experimental studies were conducted to provide insight into these scenarios. This included experiments studying the evolution/dispersion of a hydrogen cloud following a liquid release and the generation of electrostatic charges in hydrogen plumes and pipework each of which are described and discussed. In addition assessment of the physical phase of the hydrogen flow within the pipework (i.e. liquid gas or two phase) was investigated. The objectives experimental set up and result summary are provided. Data generated from these experiments is to be used to generate and validate theoretical models and ultimately contribute to the development of regulations codes and standards for the storage handling and use of liquid hydrogen.

Green liquid hydrogen (LH2) could play an essential role as a zero-carbon aircraft fuel to reach long-term sustainable aviation. Excluding challenges such as electrolysis transportation and use of renewable energy in setting up hydrogen (H2) fuel infrastructure this paper investigates the interface between refueling systems and aircraft and the impacts on fuel distribution at the airport. Furthermore it provides an overview of key technology design decisions for LH2 refueling procedures and their effects on the turnaround times as well as on aircraft design. Based on a comparison to Jet A-1 refueling new LH2 refueling procedures are described and evaluated. Process steps under consideration are connecting/disconnecting purging chill-down and refueling. The actual refueling flow of LH2 is limited to a simplified Reynolds term of v · d = 2.35 m2/s. A mass flow rate of 20 kg/s is reached with an inner hose diameter of 152.4 mm. The previous and subsequent processes (without refueling) require 9 min with purging and 6 min without purging. For the assessment of impacts on LH2 aircraft operation process changes on the level of ground support equipment are compared to current procedures with Jet A-1. The technical challenges at the airport for refueling trucks as well as pipeline systems and dispensers are presented. In addition to the technological solutions explosion protection as applicable safety regulations are analyzed and the overall refueling process is validated. The thermodynamic properties of LH2 as a real compressible fluid are considered to derive implications for airport-side infrastructure. The advantages and disadvantages of a subcooled liquid are evaluated and cost impacts are elaborated. Behind the airport storage tank LH2 must be cooled to at least 19 K to prevent two-phase phenomena and a mass flow reduction during distribution. Implications on LH2 aircraft design are investigated by understanding the thermodynamic properties including calculation methods for the aircraft tank volume and problems such as cavitation and two-phase flows. In conclusion the work presented shows that LH2 refueling procedure is feasible compliant with the applicable explosion protection standards and hence does not impact the turnaround procedure. A turnaround time comparison shows that refueling with LH2 in most cases takes less time than with Jet A-1. The turnaround at the airport can be performed by a fuel truck or a pipeline dispenser system without generating direct losses i.e. venting to the atmosphere.

This paper discloses the architecture and related performance of an environment control system designed to be integrated within a complex multi-functional thermal and energy management system that manages the heat loads and generation of electric power in a hypersonic vehicle by benefitting from the presence of cryogenic liquid hydrogen onboard. A bleed-less architecture implementing an open-loop cycle with a boot-strap sub-freezing air cycle machine is suggested. Hydrogen boil-off reveals to be a viable cold source for the heat exchangers of the system as well as for the convective insulation layer designed around the cabin walls. Including a 2 mm boil-off convective layer into the cabin cross-section proves to be far more effective than a more traditional air convective layer of approximately 60 mm. The application to STRATOFLY MR3 a Mach 8 waverider cruiser using liquid hydrogen as propellant confirmed that presence of cryogenic tanks provides up to a 70% reduction in heat fluxes entering the cabin generated outside of it but inside the vehicle by the propulsive system and other onboard systems. The effectiveness of the architecture was confirmed for all Mach numbers (from 0.3 to 8) and all flight altitudes (from sea level to 35 km).

The Low Carbon Hydrogen Standard sets a maximum threshold for the amount of greenhouse gas emissions allowed in the production process for hydrogen to be considered ‘low carbon hydrogen’. Compliance with the standard will help ensure new low carbon hydrogen production makes a direct contribution to our carbon reduction targets.

This guidance sets out the methodology for calculating the emissions associated with hydrogen production and the steps producers should take to prove that the hydrogen they produce is compliant with the standard.

It is for use by hydrogen producers seeking support from government schemes and policies that have adopted the standard.

The standard requires hydrogen producers to:

• meet a GHG emissions intensity of 20g CO2e/MJLHV of produced hydrogen or less for the hydrogen to be considered low carbon
• calculate their greenhouse gas (GHG) emissions up to the ‘point of production’
• set out a risk mitigation plan for fugitive hydrogen emissions
• meet additional requirements for the use of biogenic inputs where relevant and as appropriate for the feedstock source and classification

The transition to energy systems with a high share of renewable energy depends on the availability of technologies that can connect the physical distances or bridge the time differences between the energy supply and demand points. This study focuses on energy storage technologies due to their expected role in liberating the energy sector from fossil fuels and facilitating the penetration of intermittent renewable sources. The performance of 27 energy storage alternatives is compared considering sustainability aspects by means of data envelopment analysis. To this end storage alternatives are first classified into two clusters: fast-response and long-term. The levelized cost of energy energy and water consumption global warming potential and employment are common indicators considered for both clusters while energy density is used only for fast-response technologies where it plays a key role in technology selection. Flywheel reveals the highest efficiency between all the fast-response technologies while green ammonia powered with solar energy ranks first for long-term energy storage. An uncertainty analysis is incorporated to discuss the reliability of the results. Overall results obtained and guidelines provided can be helpful for both decision-making and research and development purposes. For the former we identify the most appealing energy storage options to be promoted while for the latter we report quantitative improvement targets that would make inefficient technologies competitive if attained. This contribution paves the way for more comprehensive studies in the context of energy storage by presenting a powerful framework for comparing options according to multiple sustainability indicators.

The hydrogen dispersion phenomenon in an enclosure depends on the ratio of the gas buoyancy induced momentum. Random diffusive motions of individual gas particles become dominative when the release momentum is low. Then a uniform hydrogen concentration appears in the enclosure instead of the gas stratification below the ceiling. The paper justifies this hypothesis by demonstrating fullscale experimental results of hydrogen dispersion within a confined space under six different release variations. During the experiments hydrogen was released into the test room of 60 m3 volume in two methods: through a nozzle and through 21 points evenly distributed on the emission box cover (multipoint release). Each release method was tested with three different hydrogen volume flow rates (3.17·10−3 m3/s 1.63·10−3 m3/s 3.34·10−4 m3/s). The tests confirm the increase of hydrogen convective upward flow and its stratification tendency relative to increased volume flow. A tendency of more uniform hydrogen cloud distribution when Mach Reynolds and Froud number values decreased was demonstrated. Because the hydrogen dispersion phenomena impact fire and explosive hazards the presented experimental results could help fire protection systems be in an enclosure designed allowing their effectiveness optimization.

The WGS reaction is an exothermic reaction between carbon monoxide and steam to form carbon dioxide and hydrogen. This reaction which has been used industrially for more than 100 years has recently received a great deal of attention from researchers as one of the ways to produce environmentally acceptable hydrogen from fossil fuels in large quantities. For the application of this reaction on an industrial scale the key is choosing the optimal catalysts that can ensure high CO conversion and have a long lifetime under industrial conditions. Therefore new types of catalysts are being developed that meet these requirements better than the Fe- and Cu-based catalysts commonly used in the past. The WGSR on a commercial nickel-based catalyst and a laboratory-prepared copper and cobalt-based catalyst was tested in a laboratory apparatus set up at the University of Chemistry and Technology Prague. The best performance of the laboratory-prepared catalyst was observed for the catalyst with a Cu content of 14.8 wt% and activated in a hydrogen atmosphere. The laboratory-prepared Co-based catalyst showed good WGSR activity in the temperature range of 200–450 ◦C although this was always inferior to that of the Cu-based catalyst. When subjected to the feed gas containing 0.4 mole% H2S the Co-based catalyst showed good resistance to sulphur poisoning. Therefore Co-based catalysts can be considered good sulphur-tolerant intermediate temperature WGSR catalysts.

Aviation is the backbone of our modern society. In 2019 around 4.5 billion passengers travelled through the air. However at the same time aviation was also responsible for around 5% of anthropogenic causes of global warming. The impact of the COVID-19 pandemic on the aviation sector in the short term is clearly very high but the long-term effects are still unknown. However with the increase in global GDP the number of travelers is expected to increase between three- to four-fold by the middle of this century. While other sectors of transportation are making steady progress in decarbonizing aviation is falling behind. This paper explores some of the various options for energy carriers in aviation and particularly highlights the possibilities and challenges of using cryogenic fuels/energy carriers such as liquid hydrogen (LH2) and liquefied natural gas (LNG).

There is renewed interest in hydrogen as an alternative fuel for aero engines due to their perceived environmental and performance benefits compared to jet fuel. This paper presents a cycle thermal performance energy and creep life assessment of hydrogen compared with jet fuel using a turbofan aero engine. The turbofan cycle performance was simulated using a code developed by the authors that allows hydrogen and jet fuel to be selected as fuel input. The exergy assessment uses both conservations of energy and mass and the second law of thermodynamics to understand the impact of the fuels on the exergy destruction exergy efficiency waste factor ratio environmental effect factor and sustainability index for a turbofan aero engine. Finally the study looks at a top-level creep life assessment on the high-pressure turbine hot section influenced by the fuel heating values. This study shows performance (64% reduced fuel flow rate better SFC) and more extended blade life (15% increase) benefits using liquefied hydrogen fuel which corresponds with other literary work on the benefits of LH2 over jet fuel. This paper also highlights some drawbacks of hydrogen fuel based on previous research work and gives recommendations for future work aimed at maturing the hydrogen fuel concept in aviation.

This study aimed to identify the impact of achieving the 1.5 ◦C target on the petroleum supply chain in Japan and discuss the feasibility and challenges of decarbonization. First a national material flow was established for the petroleum supply chain in Japan including processes for crude petroleum refining petroleum product manufacturing plastic resin and product manufacturing and by-product manufacturing. In particular by-product manufacturing processes such as hydrogen gaseous carbon dioxide and sulfur were selected because they are utilized in other industries. Next the outlook for the production of plastic resin hydrogen dry ice produced from carbon dioxide gas and sulfur until 2050 was estimated for reducing petroleum consumption required to achieve the 1.5 ◦C target. As a result national petroleum treatment is expected to reduce from 177048.00 thousand kl in 2019 to 126643.00 thousand kl in 2030 if the reduction in petroleum consumption is established. Along with this decrease plastic resin production is expected to decrease from 10500.00 thousand ton in 2019 to 7511.00 thousand ton by 2030. Conversely the plastic market is expected to grow steadily and the estimated plastic resin production in 2030 is expected to be 20079.00 thousand ton. This result indicates that there is a large output gap between plastic supply and demand. To mitigate this gap strongly promoting the recycling of waste plastics and making the price competitiveness of biomass plastics equal to that of petroleum-derived plastics are necessary

The effects of different mole fractions of hydrogen and carbon dioxide on the combustion characteristics of a premixed methane–air mixture are experimentally and numerically investigated. The laminar burning velocity of hydrogen-methane-carbon dioxide-air mixture was measured using the spherically expanding flame method at the initial temperature and pressure of 283 K and 0.1 MPa respectively. Additionally numerical analysis is conducted under steady 1D laminar flow conditions to investigate the adiabatic flame temperature and dominant elementary reactions. The measured velocities correspond with those estimated numerically. The results show that increasing the carbon dioxide mole fraction decreases the laminar burning velocity attributed to the carbon dioxide dilution which decreases the thermal diffusivity and flame temperature. Conversely the velocity increases with the thermal diffusivity as the hydrogen mole fraction increases. Moreover the hydrogen addition leads to chain-branching reactions that produce active H O and OH radicals via the oxidation of hydrocarbons which is the rate-determining reaction.

The Power-to-Gas (PtG) process chain could play a significant role in the future energy system. Renewable electric energy can be transformed into storable methane via electrolysis and subsequent methanation. This article compares the available electrolysis and methanation technologies with respect to the stringent requirements of the PtG chain such as low CAPEX high efficiency and high flexibility. Three water electrolysis technologies are considered: alkaline electrolysis PEM electrolysis and solid oxide electrolysis. Alkaline electrolysis is currently the cheapest technology; however in the future PEM electrolysis could be better suited for the PtG process chain. Solid oxide electrolysis could also be an option in future especially if heat sources are available. Several different reactor concepts can be used for the methanation reaction. For catalytic methanation typically fixed-bed reactors are used; however novel reactor concepts such as three-phase methanation and micro reactors are currently under development. Another approach is the biochemical conversion. The bioprocess takes place in aqueous solutions and close to ambient temperatures. Finally the whole process chain is discussed. Critical aspects of the PtG process are the availability of CO2 sources the dynamic behaviour of the individual process steps and especially the economics as well as the efficiency.

Policymakers and global energy models are increasingly looking towards hydrogen as an enabling energy carrier to decarbonize hard-to-abate sectors (projecting growth in hydrogen consumption in the magnitude of hundreds of megatons). Combining scenarios from global energy models and life cycle impacts of different hydrogen production technologies the results of this work show that the life cycle emissions from proposed configurations of the hydrogen economy would lead to climate overshoot of at least 5.4–8.1x of the defined “safe” space for greenhouse gas emissions by 2050 and the cumulative consumption of 8–12% of the remaining carbon budget. This work suggests a need for a science-based definition of “clean” hydrogen agnostic of technology and compatible with a “safe” development of the hydrogen economy. Such a definition would deem blue hydrogen environmentally unviable by 2025–2035. The prolific use of green hydrogen is also problematic however due to the requirement of a significant amount of renewable energy and the associated embedded energy land and material impacts. These results suggest that demand-side solutions should be further considered as the large-scale transition to hydrogen which represents a “clean” energy shift may still not be sufficient to lead humanity into a “safe” space.

Thermochemical hydrogen production process is one of the candidates of industrial fossil fuel free hydrogen production. Japan Atomic Energy Agency (JAEA) has been conducting R&D of the thermochemical water splitting iodine-sulfur (IS) process since the end of 1980s. This paper presents the recent study on the IS process in JAEA. In 2005-2009 test-fabrication of components collection of design database improvement of process components for higher thermal efficiency and proposition of composition measurement method were carried out. On the basis of them the integrity test of process components is carried out in 2010-2014 to examine their integrities in severe process environments. At present a Bunsen reactor which produces acids and incidental equipments has been already manufactured using corrosion resistant materials such as glass lining steel and fluoroplastic lining steel. Flow tests to examine the functionality and integrity of the materials are planned in 2012.

Water electrolysis powered by renewables provides a green approach to hydrogen production to support the ‘‘hydrogen economy.’’ However the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are tightly coupled in both time and space in traditional water electrolysis which brings inherent operational challenges such as the mixture of H2/O2 and the limited HER rate caused by the sluggish kinetics of OER. Against this background decoupling H2 and O2 production in water electrolysis by using the auxiliary redox mediator was first proposed in 2013 in which O2 and H2 are produced at different times rates and/or locations. The decoupling strategy offers not only a new way to facilitate renewables to H2 but it can also be applied in other chemical or electrochemical processes. This review describes recent efforts to develop high-performance redox mediators optimized strategies in decoupled water electrolysis the design of electrolyzer configuration the challenges faced and the prospective directions.

The use of hybrid renewable energy systems (HRES) has become the best option for supplying electricity to sites remote from the central power system because of its sustainability environmental friendliness and its low cost of energy compared to many conventional sources such as diesel generators. Due to the intermittent nature of renewable energy resources there is a need however for an energy storage system (ESS) to store the surplus energy and feed the energy deficit. Most renewable sources used battery storage systems (BSS) a green hydrogen storage system (GHSS) and a diesel generator as a backup for these sources. Batteries are very expensive and have a very short lifetime and GHSS have a very expensive initial cost and many security issues. In this paper a system consisting of wind turbines and a photovoltaic (PV) array with a pumped hydro energy storage (PHES) system as the main energy storage to replace the expensive and short lifetime batteries is proposed. The proposed system is built to feed a remote area called Dumah Aljandal in the north of Saudi Arabia. A smart grid is used via a novel demand response strategy (DRS) with a dynamic tariff to reduce the size of the components and it reduces the cost of energy compared to a flat tariff. The use of the PHES with smart DRS reduced the cost of energy by 34.2% and 41.1% compared to the use of BSS and GHSS as an ESS respectively. Moreover the use of 100% green energy sources will avoid the emission of an estimated 2.5 million tons of greenhouse gases every year. The proposed system will use a novel optimization algorithm called the gradually reduced particles of particle swarm optimization (GRP-PSO) algorithm to enhance the exploration and exploitation during the searching iterations. The GRP-PSO reduces the convergence time to 58% compared to the average convergence time of 10 optimization algorithms used for comparison. A sensitivity analysis study is introduced in this paper in which the effect of ±20% change in wind speed and solar irradiance are selected and the system showed a low effect of these resources on the Levelized cost of energy of the HRES. These outstanding results proved the superiority of using a pumped-storage system with a dynamic tariff demand response strategy compared to the other energy storage systems with flat-rate tariffs.

As the need for duplex stainless steel (DSS) increases it is necessary to evaluate hydrogen stress cracking (HSC) in dissimilar welded joints (WJs) of DSS and carbon steel. This study aims to investigate the effect of the weld microstructure on the HSC behaviour of dissimilar gas-tungsten arc welds of DSS and carbon steel. In situ slow-strain rate testing (SSRT) with hydrogen charging was conducted for transverse WJs which fractured in the softened heat-affected zone of the carbon steel under hydrogen-free conditions. However HSC occurred at the martensite band and the interface of the austenite and martensite bands in the type-II boundary. The band acted as an HSC initiation site because of the presence of a large amount of trapped hydrogen and a high strain concentration during the SSRT with hydrogen charging. Even though some weld microstructures such as the austenite and martensite bands in type-II boundaries were harmless under normal hydrogen-free conditions they had a negative effect in a hydrogen atmosphere resulting in the premature rupture of the weld. Eventually a premature fracture occurred during the in situ SSRT in the type-II boundary because of the hydrogen-enhanced strain-induced void (HESIV) and hydrogen-enhanced localised plasticity (HELP) mechanisms.

The demand for fossil fuels is increasing because of globalization and rising energy demands. As a result many nations are exploring alternative energy sources and hydrogen is an efficient and practical alternative fuel. In the transportation industry the development of hydrogen-powered cars aims to maximize fuel efficiency and significantly reduce exhaust gas emission and concentration. The impact of using hydrogen as a supplementary fuel for spark ignition (SI) and compression ignition (CI) engines on engine performance and gas emissions was investigated in this study. By adding hydrogen as a fuel in internal combustion engines the torque power and brake thermal efficiency of the engines decrease while their brake-specific fuel consumption increase. This study suggests that using hydrogen will reduce the emissions of CO UHC CO2 and soot; however NOx emission is expected to increase. Due to the reduction of environmental pollutants for most engines and the related environmental benefits hydrogen fuel is a clean and sustainable energy source and its use should be expanded.

In order to ensure the safety of shore-based hydrogen bunkering operations this paper takes a 2000-ton bulk hydrogen powered ship as an example. Firstly the HAZID method is used to identify the hazards of hydrogen bunkering then the probability of each scenario is analyzed and then the consequences of scenarios with high risk based on FLACS software is simulated. Finally the personal risk of bunkering operation is evaluated and the bunkering restriction area is defined. The results show that the personal risk of shore-based bunkering operation of hydrogen powered ship is acceptable but the following risk control measures should be taken: (1) The bunkering restriction area shall be delineated and only the necessary operators are allowed to enter the area and control the any form of potential ignition source; (2) The hose is the high risk hazards during bunkering. The design form of bunkering arm and bunkering hose is considered to shorten the length of the hose as far as possible; (3) A safe distance between shore-based hydrogenation station and the building outside the station should be guaranteed. The results have a guiding role in effectively reducing the risk of hydrogen bunkering operation.

This paper presents experiments performed at Canadian Nuclear Laboratories (CNL) to examine the dispersion behaviour of helium in a polycarbonate enclosure that was representative of a residential parking garage. The purpose was to gain a better understanding of the effect of buoyancy- or winddriven natural ventilation on hydrogen dispersion behaviour. Although hydrogen dispersion studies have been reported extensively in the literature gaps still exist in predictive methods for hazard analysis. Helium a simulant for hydrogen was injected near the centre of the floor with a flow rate ranging from 5 to 75 standard litres per minute through an upward-facing nozzle resulting in an injection Richardson number ranging between 10-1 and 102. The location of the nozzle varied from the bottom of the enclosure to near the ceiling to examine the impact of the nozzle elevation on the development of a stratified layer in the upper region of the enclosure. When the injection nozzle was placed at a sufficiently low elevation the vertical helium profile always consisted of a homogenous layer at the top overlaying a stratified layer at the bottom. To simulate outdoor environmental conditions a fan was placed in front of each vent to examine the effect of opposing or assisting wind on the dispersion. The helium transients in the uniform layer predicted with analytical models were in good agreement with the measured transients for the tests with injection at lower elevations or with no wind. Model improvements are required for adequately predicting transients with significantly stratified profiles or with wind.

The H₂ internal combustion engine (ICE) is a key technology for complete decarbonization of the transport sector. To match or exceed the power density of conventional combustion engines H₂ direct injection (DI) is essential. Therefore new injector concepts that meet the requirements of a H₂ operation have to be developed. The macroscopic free stream behavior of H2 released from an innovative fluidic oscillating nozzle is investigated and compared with that of a conventional multi-hole nozzle. This work consists of H₂ flow measurements and injection tests in a constant volume chamber using the Schlieren method and is accompanied by a LES simulation. The results show that an oscillating H₂ free stream has a higher penetration velocity than the individual jets of a multi-hole nozzle. This behavior can be used to inject H₂ far into the combustion chamber in the vertical direction while the piston is still near bottom dead center. As soon as the oscillation of the H₂ free stream starts the spray angle increases and therefore H2 is also distributed in the horizontal direction. In this phase of the injection process spray angles comparable to those of a multi-hole nozzle are achieved. This behavior has a positive effect on H2 homogenization which is desirable for the combustion process.

Reducing green‐house gases emission from light‐duty vehicles is compulsory in order to slow down the climate change. The application of High Frequency Ignition systems based on the Corona discharge effect has shown the potential to extend the dilution limit of engine operating conditions promoting lower temperatures and faster combustion events thus higher thermal and indicating efficiency. Furthermore predicting the behavior of Corona ignition devices against new sustainable fuel blends including renewable hydrogen and biogas is crucial in order to deal with the short‐intermediate term fleet electric transition. The numerical evaluation of Corona‐induced discharge radius and radical species under those conditions can be helpful in order to capture local effects that could be reached only with complex and expensive optical investigations. Using an ex‐ tended version of the Corona one‐dimensional code previously published by the present authors the simulation of pure methane and different methane–hydrogen blends and biogas–hydrogen blends mixed with air was performed. Each mixture was simulated both for 10% recirculated exhaust gas dilution and for its corresponding dilute upper limit which was estimated by means of chemical kinetics simulations integrated with a custom misfire detection criterion.

Across Europe permitted blend levels of hydrogen blending into the gas grid are appreciably higher than that currently permitted in the UK up to 12% mol/mol compared with 0.1% mol/mol. Whilst there is some routine blending undertaking – typically power to gas applications three major projects have been undertaken to demonstrate operation of a gas distribution network at higher blend levels of hydrogen.<br/>A Dutch project was completed in 2011 which demonstrated successful operation into a network with new appliances at 20% mol/mol. A German project was completed in 2015 which demonstrated successful operation into an existing gas network with existing appliances at their permitted level of 10% mol/mol. In France an extensive programme is underway to inject hydrogen into a network at 20% mol/mol due to commence injection in 2018.<br/>Each of these projects undertook extensive pre-trial activities and operational data was collected during the Dutch and German trials. The programme of pre-trial work for the French project was particularly extensive and mirrored the work done by HyDeploy. This led to a permit being granted for the French project at 20% mol/mol with injection into the network imminent.<br/>The HyDeploy team has engaged with each of the project teams who have been very co-operative; this has enabled scientific sharing of best practice. In all cases the projects were successful. The participants in the Dutch project were particularly keen to have been able to undertake a similar trial to HyDeploy; a larger trial into existing appliances. However political changes in Holland have precluded that at this time such progress was not limited by technical findings from the work.<br/>A high level overview of the projects and the data provided is summarised in this report. More detailed information is referenced and covered in more detail where required in the appropriate individual topic reports supporting the Exemption.<br/>Click on supplements tab to view the other documents from this report

The computational thermodynamic analysis of a samarium oxide-based two-step solar thermochemical water splitting cycle is reported. The analysis is performed using HSC chemistry software and databases. The first (solar-based) step drives the thermal reduction of Sm2O3 into Sm and O2. The second (non-solar) step corresponds to the production of H2 via a water splitting reaction and the oxidation of Sm to Sm2O3. The equilibrium thermodynamic compositions related to the thermal reduction and water splitting steps are determined. The effect of oxygen partial pressure in the inert flushing gas on the thermal reduction temperature (TH) is examined. An analysis based on the second law of thermodynamics is performed to determine the cycle efficiency (ηcycle) and solar-to-fuel energy conversion efficiency (ηsolar´to´fuel) attainable with and without heat recuperation. The results indicate that ηcycle and ηsolar´to´fuel both increase with decreasing TH due to the reduction in oxygen partial pressure in the inert flushing gas. Furthermore the recuperation of heat for the operation of the cycle significantly improves the solar reactor efficiency. For instance in the case where TH = 2280 K ηcycle = 24.4% and ηsolar´to´fuel = 29.5% (without heat recuperation) while ηcycle = 31.3% and ηsolar´to´fuel = 37.8% (with 40% heat recuperation).

The Hydrogen Incidents and Accidents Database (HIAD) is an international open communication platform collecting systematic data on hydrogen-related undesired incidents which was initially developed in the frame of HySafe an EC co-funded Network of Excellence in the 6th Frame Work Programme by the Joint Research Centre of the European Commission (EC-JRC). It was updated by JRC as HIAD 2.01 in 2016 with the support of the Fuel Cells and Hydrogen 2 Joint Undertaking (FCH 2 JU). Since the launch of the European Hydrogen Safety Panel2 (EHSP) initiative in 2017 by FCH 2 JU the EHSP has worked closely with JRC to upload additional/new incidents to HIAD 2.0 and analyze them to gather statistics lessons learnt and recommendations through Task Force 3. The first report to summarise the findings of the analysis was published by FCH 2 JU in September 2019. Since the publication of the first report the EHSP and JRC have continuously worked together to enlarge HIAD 2.0 by adding newly occurred incidents as well as quality historic incidents which were not previously uploaded to HIAD 2.0. This has facilitated the number of validated incidents in HIAD 2.0 to increase from 272 in 2018 to 593 in March 2021. This number is also dynamic and continues to increase as new incidents are being continuously added by both EHSP and JRC; and validated by JRC. The overall quality of the published incidents has also been improved whenever possible. For example additional information has been added to some existing incidents. Since mid-2020 EHSP Task Force TF3 has further analysed the 485 events which were in the database as of July 2020. For completeness of the statistics these include the events considered in our first report3 as well as the newly added/validated events since then. In this process the EHSP has also re-visited the lessons learnt in the first report to harmonise the approaches of analysis and improve the overall analysis. The analysis has comprehensively covered statistics lessons learnt and recommendations. The increased number of incidents has also made it viable to extract statistics from the available incidents at the time of the analysis including previously available incidents. It should be noted that some incidents reported is of low quality therefore it was not included in the statistical analysis.

Natural gas pipelines have attracted increasing attention in the energy industry thanks to the current demand for green energy and the advantages of pipeline transportation. A novel deep learning method is proposed in this paper using a coupled network structure incorporating the thermodynamics-informed neural network and the compressor Boolean neural network to incorporate both functions of pipeline transportation safety check and energy supply predictions. The deep learning model is uniformed for the coupled network structure and the prediction efficiency and accuracy are validated by a number of numerical tests simulating various engineering scenarios including hydrogen gas pipelines. The trained model can provide dispatchers with suggestions about the number of phases existing during the transportation as an index showing safety while the effects of operation temperature pressure and compositional purity are investigated to suggest the optimized productions.