Publications

Decarbonization of energy economy is nowadays a topical theme and several pathways are under discussion. Gaseous fuels have a fundamental role for this transition and the production of low carbon-impact fuels is necessary to deal with this challenge. The generation of renewable hydrogen is a trusted solution since this energy vector can be promptly produced from electricity and injected into the existing natural gas infrastructure granting storage capacity and easy transportation. This scenario will lead in the near future to hydrogen enrichment of natural gas whose impact on the infrastructures is being actively studied. The effect on end-user devices such as domestic gas boilers instead is still little analyzed and tested but is fundamental to be assessed. The aim of this research is to generate knowledge on the effect of hydrogen enrichment on the widely used premixed boilers: the investigations include pollutant emissions efficiency flashback and explosion hazard control system and materials selection. A model for calculating several parameters related to combustion of hydrogen enriched natural gas is presented. Guidelines for the design of new components are provided and an insight is given on the maximum hydrogen blending bearable by the current boilers.

Of all the sectors in the UK decarbonising heat remains one of the most challenging. Heat used for industrial domestic and commercial purposes generates around a third of all UK carbon emissions 70% of which is due to burning natural gas. In order to meet our legally binding national climate change targets unabated natural gas use for heat must be phased out. Low carbon gas - including hydrogen and biogases - is one option to replace it. The Future Gas Series examines the opportunities and challenges associated with using low carbon gas to help decarbonise the UK economy.<br/><br/>This is the second report in the three-part Future Gas Series. Part 1: Next Steps for the Gas Grid explored the potential to decarbonise the existing gas grid. The report Part 2: the Production of Low Carbon Gas focuses on the issues related to the production of low carbon gas. It considers the different production technologies the potential scale of deployment of each method and the potential feedstocks. It also discusses issues related to bulk transport and storage of gas. Put together from expert evidence from across industry and academia it provides a balanced guide for policy makers in this area. It was a co-chaired by James Heappey MP (Conservative) Alan Whitehead MP (Labour) and Alistair Carmichael MP (SNP).<br/><br/>Carbon Connect suggests that biogases- such as biomethane and bioSNG- provide low regrets opportunities in the near term to provide low carbon heat and could also potentially make use of waste that would otherwise go to landfill.  However they require further support to allow them to continue contributing to decarbonising the UK economy. Hydrogen could provide huge decarbonisation opportunities and has applications across the energy system from putting hydrogen in the gas grid to be burnt for heat in homes to hydrogen buses and trains. However to realise this potential a market for hydrogen must be built up. This should incentivise business to invest in hydrogen technologies reward those who use hydrogen and build up hydrogen infrastructure.<br/><br/>

The central objective of this study is to improve the understanding of flow behaviour during hydrogen (H2) storage in subsurface porous media with a cushion gas of carbon dioxide (CO2). In this study we investigate the interactions between various factors driving the flow behaviour including the underlying permeability heterogeneity viscous instability and the balance between the viscous and gravity forces. In particular we study the impact of CO2 solubility in water on the level of H2 purity. This effect is demonstrated for the first time in the context of H2 storage. We have performed a range of 2D vertical cross-sectional simulations at the decametre scale with a very fine cell size (0.1 m) to capture the flow behaviour in detail. This is done since it is at this scale that much of the mixing between injected and native fluids occurs in physical porous media. It is found that CO2 solubility may have different (positive and negative) impacts on the H2 recovery performance (i.e. on the purity of the produced H2) depending on the flow regimes in the system. In the viscous dominated regime the less viscous H2 may infiltrate and bypass the cushion gas of CO2 during the period of H2 injection. This leads to a quick and dramatic reduction in the H2 purity when back producing H2 due to the co-production of the previously bypassed CO2. Interestingly the impurity levels in the H2 are much less severe in the case when CO2 solubility in water is considered. This is because the bypassed CO2 will redissolve into the water surrounding the bypassed zones which greatly retards the movement of CO2 towards the producer. In the gravity dominated scenario H2 accumulates at the top of the model and displaces the underlying cushion gas in an almost piston-like fashion. Approximately 58% of H2 can be recovered at a purity level above 98% (combustion requirements by ISO) in this gravity-dominated case. However when CO2 solubility is considered the H2 recovery performance is slightly degraded. This is because the dissolved CO2 is also gradually vaporised during H2 injection which leads to an expansion of mixing zone of CO2 and H2. This in turn reduces the period of high H2 purity level (>98%) during back-production.

Hydrogen is fast becoming a new international “super fuel” to accelerate global climate change ambitions. This paper has two inter-weaving themes. Contextually it focuses on the potential impact of the EU’s new Carbon Border Adjustment Mechanism (CBAM) on fossil fuel-generated as opposed to green hydrogen imports. The CBAM as a transnational carbon adjustment mechanism has the potential to impact international trade in energy. It seeks both a level playing field between imports and EU internal markets (subject to ambitious EU climate change policies) and to encourage emissions reduction laggards through its “carbon diplomacy”. Countries without a price on carbon will be charged for embodied carbon in their supply chains when they export to the EU. Empirically we focus on two hydrogen export/import case studies: Australia as a non-EU state with ambitions to export hydrogen and Germany as an EU Member State reliant on energy imports. Energy security is central to energy trade debates but needs to be conceptualized beyond supply and demand economics to include geopolitics just transitions and the impacts of border carbon taxes and EU carbon diplomacy. Accordingly we apply and further develop a seven-dimension energy security-justice framework to the examples of brown blue and green hydrogen export/import hydrogen operations with varying carbon-intensity supply chains in Australia and Germany. Applying the framework we identify potential impact—risks and opportunities—associated with identified brown blue and green hydrogen export/import projects in the two countries. This research contributes to the emerging fields of international hydrogen trade supply chains and international carbon diplomacy and develops a potentially useful seven-dimension energy security-justice framework for energy researchers and policy analysts.

A stable energy supply will require balancing the fluctuations of renewable energy generation due to the transition to renewable energy sources. Intraday and seasonal storage systems are often limited to local geographical or infrastructural circumstances. This study experimentally verifies the application of inexpensive and abundant natural iron ores for energy storage with combined hydrogen and heat release. The incorporated iron oxides are reduced with hydrogen from electrolysis to store energy in chemically bonded form. The on–demand reoxidation releases either pure hydrogen or high-temperature heat as valuable products. Natural iron ores as storage material are beneficial as the specific costs are lower by an order of magnitude compared to synthetic iron oxide-based materials. Suitable iron ores were tested in TG analysis and in a 1 kW fixed-bed reactor. Siderite a carbonate iron ore was verified as promising candidate as it shows significantly lower reaction temperatures and twice the storage capacity over other commercial iron ores such as ilmenite. The specific storage costs are as low as 80–150 $ per MWh hydrogen stored based on the experimental in-situ tests. The experimentally determined volumetric energy storage capacity for the bulk material was 1.7 and 1.8 MWh m− 3 for hydrogen and heat release respectively. The raw siderite ore was stable for over 50 consecutive cycles at operating temperatures of 500–600 ◦C in in-situ lifetime tests. The combination of high abundance low price and reasonable capacity can thus result in very low specific energy storage costs. The study proofs that suitable natural iron ores are an interesting economic solution for large-scale and seasonal energy storage systems.

The use of drop-in capable alternative fuels in aircraft can support the European aviation sector to achieve its goals for sustainable development. They can be a transitional solution in the short and medium term as their use does not require any structural changes to the aircraft powertrain. However the production of alternative fuels is often energy-intensive and some feedstocks are associated with harmful effects on the environment. In addition alternative fuels are often more expensive to produce than fossil kerosene which can make their use unattractive. Therefore this paper analyzes the environmental and economic impacts of four types of alternative fuels compared to fossil kerosene in a well-to-wake perspective. The fuels investigated are sustainable aviation fuels produced by power-to-liquid and biomass-to-liquid pathways. Life cycle assessment and life cycle costing are used as environmental and economic assessment methods. The results of this well-towake analysis reveal that the use of sustainable aviation fuels can reduce the environmental impacts of aircraft operations. However an electricity mix based on renewable energies is needed to achieve significant reductions. In addition from an economic perspective the use of fossil kerosene ranks best among the alternatives. A scenario analysis confirms this result and shows that the production of sustainable aviation fuels using an electricity mix based solely on renewable energy can lead to significant reductions in environmental impact but economic competitiveness remains problematic.

Hydrogen as fuel has been considered as a feasible energy carry and which offers a clean and efficient alternative for transportation. During the high pressure filling the temperature in the hydrogen storage tank (HST) may rise rapidly due to the hydrogen compression. The high temperature may lead to safety problem. Thus for fast and safely refueling the hydrogen several key factors need to be considered. In the present study by the thermodynamics theories a mathematical model is established to simulate and analyze the high pressure filling process of the storage tank for the hydrogen station. In the analysis the physical parameters of normal hydrogen are introduced to make the simulation close to the actual process. By the numerical simulation for 50 MPa compressed hydrogen tank the temperature and pressure trends during filling are obtained. The simulation results for non-adiabatic filling were compared with the theoretically calculated ones for adiabatic conditions and the simulation results for non-adiabatic filling were compared with the simulation ones for adiabatic conditions. Then the influence of working pressure initial temperature mass flow rate initial pressure and inlet temperature on the temperature rise were analyzed. This study provides a theoretical research basis for high pressure hydrogen energy storage and hydrogenation technology.

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%.

Milford Haven: Energy Kingdom is a two-year project exploring what a decarbonised smart local energy system could look like for Milford Haven Pembroke and Pembroke Dock.

The project explores the potential of hydrogen as part of a multi-vector approach to decarbonisation. Central to the project and to achieving Net Zero is a commitment to engage with the community and local industry providing insight and opportunities for growth.

The ambition is to gather detailed insight into the whole energy system around Milford Haven to identify and design a future smart local energy system based on a truly multi-vector approach and comprehensive energy systems architecture.

The transition to Net Zero requires action across the economy. As the UK’s largest energy port Milford Haven is an industrial cluster that can handle 30% of total UK gas demand is home to Europe’s largest gas power station powering 3.5 million homes and businesses has ambitions to build 90MW of floating offshore wind supports 5000 jobs and injects £324m to the Pembrokeshire economy.

This work describes the outcomes of the effort to define designs of future energy system architectures combining; technology the interconnectivity between them and data; with markets trading platforms and policies; with business models and defined organisational governance. The aim of these designs is to provide:

• The basis for a roadmap for the next phases of development and implementation
• Confidence to innovators and investors in the future longevity of investments in hydrogen and
• A common basis of understanding for all stakeholders wishing to contribute to the Milford Haven: Energy Kingdom.

In  a  liquid  hydrogen  storage  tank  hydrogen  vapor  exists  above  the  cryogenic  liquid.  A  common modeling  assumption  of  a  liquid  hydrogen  tank  is  thermodynamic  equilibrium. However  this assumption may not hold in all conditions. A non-equilibrium storage tank with a pressure relief valve and a burst disc in parallel was modeled in this work. The model includes different boiling regimes to handle scenarios with high heat transfer. The model was first validated with a scenario where normal boil-off from an unused tank was compared to experimental data. Then four abnormal tank scenarios were explored: a loss of vacuum in the insulation layer a high ambient temperature (to simulate an engulfing fire) a high ambient temperature with a simultaneous loss of vacuum and high conduction through the insulation layer. The burst disc of the tank opened only in the cases with extreme heat transfer to the tank (i.e. fire with a loss of vacuum and high insulation conductivity) quickly releasing the hydrogen. In the cases with only a loss of vacuum or only external heat from fire the pressure relief valve on the tank managed to moderate the pressure below the burst disc activation pressure. The high insulation conductivity case highlights differences between the equilibrium and non-equilibrium tank models. The mass loss from the tank through the burst disc is slower using a non-equilibrium model because mass transfer from the liquid to gas phase within the tank becomes limiting. The implications of this model and how it can be used to help inform safety codes and standards are discussed.

In this fourth episode Simon Buckley and Matthew Moss from Innovate UK KTN are exploring the use of hydrogen in the global maritime industry alongside their special guest Chester Lewis Business Development Manager at Ryze Hydrogen.

This podcast can be found on their website

To address the limitations of conventional single-stack fuel cell hybrid systems using equivalent hydrogen consumption strategies this study proposes a multi-stack energy management strategy incorporating fuel cell health degradation. Leveraging a fuel cell efficiency decay model and lithium-ion battery cycle life assessment power distribution is reformulated as an equivalent hydrogen consumption optimization problem with stack degradation constraints. A hybrid Genetic Algorithm–Particle Swarm Optimization (GAPSO) approach achieves global optimization. The experimental results demonstrate that compared with the Frequency Decoupling (FD) method the GA-PSO strategy reduces hydrogen consumption by 7.03 g and operational costs by 4.78%; compared with the traditional Particle Swarm Optimization (PSO) algorithm it reduces hydrogen consumption by 3.61 g per operational cycle and decreases operational costs by 2.66%. This strategy ensures stable operation of the marine power system while providing an economically viable solution for hybrid-powered vessels.

The automotive industry sees hydrogen-powered fuel cell(FC) drives as a promising option with a high range and shortrefueling time. Current research aims to increase the profitabil-ity of the fuel cell system by reducing hydrogen consumption.This study suggests the use of an electrochemical hydrogencompressor (EHC) for hydrogen recirculation. Compared tomechanical compressors the EHC is very efficient due to thealmost isothermal conditions and due to its modular structurecan only take up a minimal amount of space in vehicles. Inaddition gas separation and purification of the hydrogentakes place in an EHC which is a significant advantage overthe standard recirculation with a blower or a jet pump. Thehigh purity of the hydrogen at the cathode outlet of the EHCalso increased partial pressure of the hydrogen at the fuel cellinlet and its efficiency. The study carried out shows that repla-cing the blower with the EHC reduces the hydrogen loss bypurging by up to ~95% and the efficiency of the FC systemcould be further improved. Thus the EHC has a great poten-tial for recycling hydrogen in FC systems in the automotiveindustry and is a great alternative to the current blower.

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 present paper deals with the investigation at conceptual level of the performance of short–medium-range aircraft with hydrogen propulsion. The attention is focused on the relationship between figures of merit related to transport capability such as passenger capacity and flight range and the parameters which drive the design of liquid hydrogen tanks and their integration with a given aircraft geometry. The reference aircraft chosen for such purpose is a box-wing short–mediumrange airplane the object of study within a previous European research project called PARSIFAL capable of cutting the fuel consumption per passenger-kilometre up to 22%. By adopting a retrofitting approach non-integral pressure vessels are sized to fit into the fuselage of the reference aircraft under the assumption that the main aerodynamic flight mechanic and structural characteristics are not affected. A parametric model is introduced to generate a wide variety of fuselage-tank cross-section layouts from a single tank with the maximum diameter compatible with a catwalk corridor to multiple tanks located in the cargo deck and an assessment workflow is implemented to perform the structural sizing of the tanks and analyse their thermodynamic behaviour during the mission. This latter is simulated with a time-marching approach that couples the fuel request from engines with the thermodynamics of the hydrogen in the tanks which is constantly subject to evaporation and depending on the internal pressure vented-out in gas form. Each model is presented in detail in the paper and results are provided through sensitivity analyses to both the technologic parameters of the tanks and the geometric parameters influencing their integration. The guidelines resulting from the analyses indicate that light materials such as the aluminium alloy AA2219 for tanks’ structures and polystyrene foam for the insulation should be selected. Preferred values are also indicted for the aspect ratios of the vessel components i.e. central tube and endcaps as well as suggestions for the integration layout to be adopted depending on the desired trade-off between passenger capacity as for the case of multiple tanks in the cargo deck and achievable flight ranges as for the single tank in the section.

Severe accidents in nuclear power plants are potentially dangerous to both humans and the environment. To prevent and/or mitigate the consequences of these accidents it is paramount to have adequate accident management measures in place. During a severe accident combustible gases — especially hydrogen and carbon monoxide — can be released in significant amounts leading to a potential explosion risk in the nuclear containment building. These gases need to be managed to avoid threatening the containment integrity which can result in the releases of radioactive material into the environment. The main objective of the AMHYCO project is to propose innovative enhancements in the way combustible gases are managed in case of a severe accident in currently operating reactors. For this purpose the AMHYCO project pursues three specific activities including experimental investigations of relevant phenomena related to hydrogen / carbon monoxide combustion and mitigation with PARs (Passive Autocatalytic Recombiners) improvement of the predictive capabilities of analysis tools used for explosion hazard evaluation inside the reactor containment as well as enhancement of the Severe Accident Management Guidelines (SAMGs) with respect to combustible gases risk management based on theoretical and experimental results. Officially launched on 1 October 2020 AMHYCO is an EU-funded Horizon 2020 project that will last 4 years from 2020 to 2024. This international project consists of 12 organizations (six from European countries and one from Canada) and is led by the Universidad Politécnica de Madrid (UPM). AMHYCO will benefit from the worldwide experts in combustion science accident management and nuclear safety in its Advisory Board. The paper will give an overview of the work program and planned outcome of the project.

NREL has been developing compliance verification tools for allowable hydrogen levels prescribed by the Global Technical Regulation Number 13 (GTR-13) for hydrogen fuel cell electric vehicles (FCEVs). As per GTR-13 FCEV exhaust is to remain below 4 vol% H2 over a 3-second moving average and shall not at any time exceed 8 vol% H2 and that this requirement is to be verified with an analyzer that has a response time of less than 300 ms. To be enforceable a means to verify regulatory requirements must exist. In response to this need NREL developed a prototype analyzer that meets the GTR metrological requirements for FCEV exhaust analysis. The analyzer was tested on a commercial fuel cell electric vehicle (FCEV) under simulated driving conditions using a chassis dynamometer at the Emissions Research and Measurement Section of Environment and Climate Change Canada and FCEV exhaust was successfully profiled. Although the prototype FCEV Exhaust Analyzer met the metrological requirements of GTR-13 the stability of the hydrogen sensor was adversely impacted by condensed water in the sample gas. FCEV exhaust is at an elevated temperature and nearly saturated with water vapor. Furthermore condensed water is present in the form of droplets. Condensed water in the sample gas collected from FCEV exhaust can accumulate on the hydrogen sensing element which would not only block access of hydrogen to the sensing element but can also permanently damage the sensor electronics. In the past year the design of the gas sampling system was modified to mitigate against the transport of liquid water to the sensing element. Laboratory testing confirmed the effectiveness of the modified sampling system water removal strategy while maintaining the measurement range and response time required by GTR-13. Testing of the upgraded analyzer design on an FCEV operating on a chassis dynamometer is scheduled for the summer of 2021.

The HyDeploy project [1] has undertaken an extensive research programme to assess safety and performance of the existing UK gas appliances population fueled with natural gas / hydrogen admixtures (hydrogen blended gas). The first stage of this work [2] focused on well maintained and normally functioning appliances. This work demonstrated that unmodified gas appliances can operate safely with hydrogen blended gas (up to 20 vol% hydrogen) and the key hazard areas of carbon monoxide (CO) production light back and flame out and the operation of flame failure devices are unaffected. It is widely recognized that due to aging and variable degrees of maintenance that the combustion performance of a gas appliance will depreciate over time. In extreme cases this can lead to situations where high levels of CO may be released back into the dwelling resulting in CO poisoning to the occupants. To obtain a universal appreciation of the effect of hydrogen addition on the safety and performance of all gas appliances operation under sub optimal conditions is required and therefore it is important that the operation of malfunctioning appliances fuelled with hydrogen blended gas is assessed. A review of failure modes identified six key scenarios where the composition of the fuel gas may lead to changes in safety performance - these primarily related to the resulting composition of the flue gas but also included delayed ignition. Gas appliance faults that will increase the CO production were tested through a series of experiments to simulate fault conditions and assess the effect of hydrogen blended gas. The fault modes examined included linting flame chilling incorrect appliance set up and modification of gas valve operation. The programme utilized six different appliances tested with three methane-hydrogen fuel blends (containing 0 20 and 28.4 vol% hydrogen). In all cases the switch to hydrogen blended gas reduced CO production. The change in CO production when using hydrogen blended gas is a consequence of a decrease in the theoretical air requirement to achieve complete combustion. In some cases the amount of CO produced was identical to the nonfault baseline performance on methane thereby fully mitigating the consequence of the malfunction. In the case of very high CO production a 90% reduction was recorded when using 20 vol% hydrogen blended gas. In situations such as non-optimal boiler set up the addition of hydrogen to the gas supply would prevent the production of high levels of CO. The findings here together with the results from HyDeploy 1 [2] indicate that the safety and performance of unmodified existing UK gas appliances are not detrimentally affected when using hydrogen blended gas. Furthermore the addition of hydrogen to the fuel gas has been shown to reduce CO production under fault conditions therefore the introduction of hydrogen into the gas network may serve to mitigate the hazard posed by existing faulty appliances that are producing elevated levels of CO.

Biomaterials attract a lot of attention as next-generation materials. Especially in the energy field fuel cells based on biomaterials can further develop clean next-generation energy and are focused on with great interest. In this study solid-state hydrogen fuel (PSII–chitin composite) composed of the photosystem II (PSII) and hydrated chitin composite was successfully created. Moreover a biofuel cell consisting of the electrolyte of chitin and the hydrogen fuel using the PSII– chitin composite was fabricated and its characteristic feature was investigated. We found that proton conductivity in the PSII–chitin composite increases by light irradiation. This result indicates that protons generate in the PSII–chitin composite by light irradiation. It was also found that the biofuel cell using the PSII–chitin composite hydrogen fuel and the chitin electrolyte exhibits the maximum power density of 0.19 mW/cm2 . In addition this biofuel cell can drive an LED lamp. These results indicate that the solid-state biofuel cell based on the bioelectrolyte “chitin” and biofuel “the PSII–chitin composite” can be realized. This novel solid-state fuel cell will be helpful to the fabrication of next-generation energy.

Hydrogen can be generated in situ within reservoirs containing hydrocarbons through chemical reactions. This technology could be a possible solution for low-emission hydrogen production due to of simultaneous CO2 storage. In gas fields it is possible to carry out the catalytic methane conversion (CMC) if sufficient amounts of steam catalyst and heat are ensured in the reservoir. There is no confirmation of the CMC’s feasibility at relatively low temperatures in the presence of core (reservoir rock) material. This study introduces the experimental results of the first part of the research on in situ hydrogen generation in the Promyslovskoye gas field. A set of static experiments in the autoclave reactor were performed to study the possibility of hydrogen generation under reservoir conditions. It was shown that CMC can be realized in the presence of core and ex situ prepared Ni-based catalyst under high pressure up to 207 atm but at temperatures not lower than 450 ◦C. It can be concluded that the crushed core model improves the catalytic effect but releases carbon dioxide and light hydrocarbons which interfere with the hydrogen generation. The maximum methane conversion rate to hydrogen achieved at 450 ◦C is 5.8%

In water-cooled nuclear power plants hydrogen gas can be generated by various mechanisms during an accident. In case combustion of the resulting hydrogen-air mixture within the facility occurs existing containment structures may be compromised and excessive radio-active material can be released to the environment. Thus an improved understanding of the propagation of lean hydrogen deflagrations within buildings and structures is essential for the development of appropriate accident management strategies associated with these scenarios. Following the accident in Fukushima Japan the application of three-dimensional computational fluid dynamics methods to high-fidelity detailed analysis of hydrogen combustion processes in both closed and vented vessels has become more widespread. In this study a recently developed large-eddy-simulation (LES) capability is applied to the prediction of lean premixed hydrogen deflagrations in vented vessels. The LES methodology makes use of a flamelet- or progress-variable-based combustion model coupled with an empirical burning velocity model (BVM) an anisotropic block-based adaptive mesh refinement (AMR) strategy an accurate finite-volume numerical scheme and a mesh independent subfilter-scale (SFS) model. Several different vessel and vent sizes and configurations are considered herein. The LES predictions are compared to experimental data obtained from the Large-Scale Vented Combustion Test Facility (LSVCTF) of the Canadian Nuclear Laboratories (CNL) with both quiescent and turbulent initial conditions. Following descriptions of the LES models LES results for both variable chamber sizes and single- and double-vent cases are presented to illustrate the capabilities of the proposed computational approach. In particular the predicted time histories of pressure as well as the maximum overpressure achieved within the vessels and combustion compartments are compared to those from the LSVCTF experiments. The influences of the modelled ignition process initial turbulence and mesh resolution on the LES results are also discussed. The findings highlight the potential and limitations of the proposed LES approach for accurately describing lean premixed hydrogen deflagrations within vented vessels.

Depleting fossil fuel resources and anthropogenic climate changes are the reasons for the intensive development of new sustainable technologies based on renewable energy sources. One of the most promising strategies is the utilization of hydrogen as an energy vector. However the limiting issue for large-scale commercialization of hydrogen technologies is a safe efficient and economical method of gas storage. In industrial practice hydrogen compression and liquefaction are currently applied; however due to the required high pressure (30–70 MPa) and low temperature (−253 ◦C) both these methods are intensively energy consuming. Chemical hydrogen storage is a promising alternative as it offers safe storage of hydrogen-rich compounds under ambient conditions. Although many compounds serving as hydrogen carriers are considered some of them do not have realistic perspectives for large-scale commercialization. In this review the three most technologically advanced hydrogen carriers—dimethyl ether methanol and dibenzyltoluene—are discussed and compared. Their potential for industrial application in relation to the energy storage transport and mobility sectors is analyzed taking into account technological and environmental aspects.

Green hydrogen production i.e. produced on a CO2 -neutral basis through the electrolysis of water employing renewable electricity has attracted increasing attention. The electricity required is generated from Renewable Energy Sources (RES) for example wind energy hydropower or solar energy. Since neither the process of production nor the end products of H2 and O2 are harmful to the environment green hydrogen is climate neutral. Developing electrolysis technology is therefore a research topic to follow. Anion Exchange Membrane (AEM) Water Electrolysis (WE) is an innovative technology that couples the advantages of the more mature technologies of Proton Exchange Membrane (PEM) and conventional alkaline electrolysis with the potential to eliminate the drawbacks of both. AEMWE technology is in an evolutionary stage and involves more investigation on several research topics such as membrane and catalyst development and stability as well as alternative feeding solutions that do not compromise the availability of fresh water. These topics are addressed in this paper mentioning the state-of-the-art materials new promising ones and providing future research directions to improve AEMWE towards a most mature technology.

In this paper the effects of hydrogen on the transport of natural gas-hydrogen mixture in a high-pressure natural gas transmission system are investigated in detail. Our research focuses on the decrease in transferable energy content under identical operating conditions as hydrogen is blended in the gas transmission network. Based on the extensive literature review the outstanding challenges and key questions of using hydrogen in the natural gas system are introduced. In our research the transmissible energy factor - TEF - is defined that quantifies the relative energy capacity of the pipeline caused by hydrogen blending. A new equation is proposed in this paper to find the value of TEF at specific pressure and temperature conditions for different hydrogen concentrations. This practical equation helps the natural gas system operators in the decision-making process when hydrogen emerges in the gas transmission system. In this paper the change of the compression power requirement which increases significantly with hydrogen blending is investigated in detail.

This study shows the results for the first time of an glycerol alkaline-acid electrolyzer. Such a configuration allows spontaneous operation producing energy and hydrogen simultaneously as a result of the utilization of the neutralization and fuel chemical energy. The electroreformer—built with a 20 wt% Pd/C anode and cathode and a Na+ -pretreated Nafion® 117—can simultaneously produce hydrogen and electricity in the low current density region whereas it operates in electrolysis mode at high current densities. In the spontaneous region the maximum power densities range from 1.23 mW cm−2 at 30 ◦C to 11.9 mW cm−2 at 90 ◦C with a concomitant H2 flux ranging from 0.0545 STP m−3 m−2 h −1 at 30 ◦C to 0.201 STP m−3 m−2 h −1 at 90 ◦C due to the beneficial effect of the temperature on the performance. Furthermore over a chronoamperometric test the electroreformer shows a stable performance over 12 h. As a challenge proton crossover from the cathode to the anode through the cation exchange Nafion® partially reduces the pH gradient responsible for the extra electromotive force thus requiring a less permeable membrane.

An uninterrupted chain of energy supplies is the core of every activity without exception for the operations of the North Atlantic Treaty Organization. A robust and efficient energy supply is fundamental for the success of missions and a guarantee of soldier safety. However organizing a battlefield energy supply chain is particularly challenging because the risks and threats are particularly high. Moreover the energy supply chain is expected to be flexible according to mission needs and able to be moved quickly if necessary. In line with ongoing technological changes the growing popularity of hydrogen is undeniable and has been noticed by NATO as well. Hydrogen is characterised by a much higher energy density per unit mass than other fuels which means that hydrogen fuel can increase the range of military vehicles. Consequently hydrogen could eliminate the need for risky refuelling stops during missions as well as the number of fatalities associated with fuel delivery in combat areas. Our research shows that a promising prospect lies in the mobile technologies based on hydrogen in combination with use of the nuclear microreactors. Nuclear microreactors are small enough to be easily transported to their destinations on heavy trucks. Depending on the design nuclear microreactors can produce 1–20 MW of thermal energy that could be used directly as heat or converted to electric power or for non-electric applications such as hydrogen fuel production. The aim of the article is to identify a model of nuclear-hydrogen synergy for use in NATO operations. We identify opportunities and threats related to mobile energy generation with nuclear-hydrogen synergy in NATO operations. The research presented in this paper identifies the best method of producing hydrogen using a nuclear microreactor. A popular and environmentally “clean” solution is electrolysis due to the simplicity of the process. However this is less efficient than chemical processes based on for example the sulphur-iodine cycle. The results of the research presented in this paper show which of the methods and which cycle is the most attractive for the production of hydrogen with the use of mini-reactors. The verification criteria include: the efficiency of the process its complexity and the residues generated as a result of the process (waste)—all taking into account usage for military purposes.

Through data mining and analysis of the word frequency and occurrence position of industrial policy keywords the main policy parameters affecting industrial development are determined and the functional relationship between industrial policy and industrial development is obtained through multi-parameter non-linear regression: Yit−1 (y1 y2 y3 y4 y5) = β1it X1 + β2it ln X2 + β3it ln X3 + β4it X1it ∗ ln X3 + εit . The time series function of the industrial development index: Y (t) = 0.174 ∗ e (0.256∗t) is established and the industrial development under the influence of next year’s policy is predicted. It is concluded from the mathematical expression of the statistical model that there is a certain coupling effect between different policies and that industrial development is influenced by the joint effect on the parent and sub-industries. This ultimately proves that there is a clear correlation between policy and industry development.

Hydrogen is an environmentally friendly source of renewable energy. Energy generation from hydrogen has not yet been widely commercialized due to issues related to risk management in its storage and transportation. In this paper the authors propose a hybrid multiple-criteria decision-making (MCDM)-based method to manage the risks involved in the storage and transportation of hydrogen (RSTH). First we identified the key points of the RSTH by examining the relevant literature and soliciting the opinions of experts and used this to build a prototype of its decision structure. Second we developed a hybrid MCDM approach called the D-ANP that combined the decision-making trial and evaluation laboratory (DEMENTEL) with the analytic network process (ANP) to obtain the weight of each point of risk. Third we used fuzzy evaluation to assess the level of the RSTH for Beijing China where energy generation using hydrogen is rapidly advancing. The results showed that the skills of the personnel constituted the most important risk-related factor and environmental volatility and the effectiveness of feedback were root factors. These three factors had an important impact on other factors influencing the risk of energy generation from hydrogen. Training and technical assistance can be used to mitigate the risks arising due to differences in the skills of personnel. An appropriate logistics network and segmented transportation for energy derived from hydrogen should be implemented to reduce environmental volatility and integrated supply chain management can help make the relevant feedback more effective.

LaNiO3 and LaCoO3 perovskites synthesized by self-combustion were characterised and studied in the ammonia decomposition reaction for obtaining hydrogen. Both the fuel to metal nitrates molar ratio and calcination temperature were found to be crucial to synthesize perovskites by self-combustion. Moreover generating non-precursor species during synthesis and small metal size were two factors which significantly influenced catalytic activity. Hence with a citric acid to metal nitrates molar ratio equal to one a LaNiO3 perovskite was obtained with suitable physicochemical properties (specific surface area lower impurities and basicity). In addition a lower calcination temperature (650 ◦C) resulted in small and well-dispersed Ni0 crystallite size after reduction which in turn promoted the catalytic transformation of ammonia into hydrogen. For cobalt perovskites calcination temperature below 900 ◦C did not have a significant influence on the size of the metallic cobalt crystallite size. The nickel and cobalt perovskite-derived catalysts calcined at 650 ◦C and 750 ◦C respectively yielded excellent H2 production from ammonia decomposition. In particular at 450 ◦C almost 100% of the ammonia was converted over the LaNiO3 under study. Furthermore these materials displayed admirable performance and stability after one day of reaction.

This report is a detailed discussion related to safety shoes heat and flame personal protective equipment (PPE) and breathing apparatus (respiratory protective equipment RPE) required for working with natural gas (NG) and hydrogen (H2). This work was undertaken by HSE Science Division (SD) as part of Phase 2a of the H21 project. This report should be read alongside all the other relevant reports generated as part of this project. Recommendations made in this report are focused solely on the provision and use of PPE and should not be considered independently of recommendations made in the other relevant reports.<br/>Understanding the similarities and difference of PPE required for NG and H2 enables a deeper understanding of how the transition from NG to 100% H2 might change the way the gas distribution network is operated and managed.

Following the release of the “Hydrogen on the Horizon” series in July and September 2021 the World Energy Council in collaboration with EPRI and PwC led a series of regional deep dives to understand regional differences within low-carbon hydrogen development. These regional deep dives aimed to uncover regional perspectives and differing dynamics for low-carbon hydrogen uptake.<br/>Although each region presents its own distinctive challenges and opportunities the deep dives revealed that the “regional paths” provide new insights into the global scaling up of low-carbon hydrogen in the coming years. In addition each region holds its own unique potential in achieving the Sustainable Development Goals.<br/>Key Takeaways:<br/>1. Our new regional insights indicate that low-carbon hydrogen can play a significant role by 2040 across the world by supporting countries’ efforts towards achieving Paris Agreement goals whilst contributing to the diversity and security of their energy portfolios. This would require significant global trade flows of hydrogen and hydrogen-based fuels.<br/>2. The momentum for hydrogen-based fuels is continuing to grow worldwide but differences are seen between regions – based on differing market activities and opportunities.<br/>3. Today moving from “whether” to “how” to develop low-carbon hydrogen highlights significant uncertainties which need to be addressed if hydrogen is to reach its full potential.<br/>Can the challenges in various supply chain options be overcome?<br/>Can hydrogen play a role in tackling climate change in the short term?<br/>Can bankable projects emerge and the gap between engineers and financers be bridged? Can the stability of supply of the main low-carbon hydrogen production sources be  guaranteed?<br/>4. Enabling low-carbon hydrogen at scale would notably require greater coordination and cooperation amongst stakeholders worldwide to better mobilise public and private finance and to shift the focus to end-users and people through the following actions:<br/>Moving from production cost to end-use price<br/>Developing Guarantees of Origin schemes with sustainability requirements<br/>Developing a global monitoring and reporting tool on low-carbon hydrogen projects<br/>Better consideration of social impacts alongside economic opportunities

An opportunity to decarbonise the offshore oil and gas sector lies in the integration of renewable energy sources with energy storage in a hybrid energy system (HES). Such concept enables maximising the exploitation of carbon-free renewable power while minimising the emissions associated with conventional power generation systems such as gas turbines. Offshore plants in addition to electrical and mechanical power also require process heat for their operation. Solutions that provide low-emission heat in parallel to power are necessary to reach a very high degree of decarbonisation. This paper investigates different options to supply process heat in offshore HES while the electric power is mostly covered by a wind turbine. All HES configurations include energy storage in the form of hydrogen tied to proton exchange membrane (PEM) electrolysers and fuel cells stacks. As a basis for comparison a standard configuration relying solely on a gas turbine and a waste heat recovery unit is considered. A HES combined with a waste heat recovery unit to supply heat proved efficient when low renewable power capacity is integrated but unable to deliver a total CO2 emission reduction higher than around 40%. Alternative configurations such as the utilization of gas-fired or electric heaters become more competitive at large installed renewable capacity approaching CO2 emission reductions of up to 80%.

Through the integration of multiple energy carriers with related technologies multi-energy systems (MES) can exploit the synergies coming from their interplay for several benefits towards decarbonization. In such a context inclusion of Power-to-X technologies in periods of excess renewable electricity supply removes the need for curtailment of renewable electricity generation. In order to achieve the environmental benefits of MES without neglecting their economic feasibility the optimal design problem is as crucial as challenging and requires the adoption of a multi-objective approach. This paper extends the results of a previous work by investigating hydrogen-based non-conventional storage for PV power in the eco-energetic optimization of an MES. The system under study consists of a reversible fuel cell (r-SOC) photovoltaic (PV) electric heat pump absorption chiller and thermal storage and allows satisfying the multi-energy needs of a residential end-user. A multi-objective linear problem is established to find the optimal MES configuration including the sizes of the involved technologies with the goal of reducing the total annual cost and the fossil primary energy input. Simulation results are compared with those obtained in previous work with a conventional nanogrid where a combined heat and power (CHP) system with gas-fired internal combustion engine and a battery were present instead of an r-SOC. The optimized configuration of the non-conventional nanogrid allows achieving a maximum primary energy reduction amounting to 66.3% compared to the conventional nanogrid. In the face of the environmental benefits the non-conventional nanogrid leads to an increase in total annual costs which compared to the conventional nanogrid is in the range of 41–65%.

Common root causes are often to be found in many if not most process safety incidents. Whilst largescale events are relatively rare such events can have devastating consequences. The subsequent investigations often uncover that the risks are rarely visible the direct causes are often hidden and that a ‘normalization of deviation’ is a common human characteristic. Process Safety Management (PSM) builds on the valuable lessons learned from past incidents to help prevent future recurrences. An understanding of how PSM originated and has evolved as a discipline over the past 200 years can be instructive when considering the safety implications of emerging technologies. An example is hydrogen production where risks must be effectively identified mitigated and addressed to provide safe production transportation storage and use .

Dilution ventilation is the current basis of safety following a flammable gas leak within a gas turbine enclosure and compliance requirements are defined for methane fuels in ISO 21789. These requirements currently define a safety criteria of a maximum flammable gas cloud size within an enclosure. The requirements are based on methane explosion tests conducted during a HSE Joint Industry Project which identified typical pressures associated with a range of gas cloud sizes. The industry standard approach is to assess the ventilation performance of specific enclosure designs against these requirements using CFD modelling. Gas turbine manufacturers are increasingly considering introducing hydrogen/methane fuel mixtures and looking towards operating with hydrogen alone. It is therefore important to review the applicability of current safety standards for these new fuels as the pressure resulting from a hydrogen explosion is expected to be significantly higher than that from a methane explosion. In this paper we replicate the previous methane explosion tests for hydrogen and hydrogen/methane fuel mixtures using the explosion modelling tool FLACS CFD. The results are used to propose updated limiting safety criteria for hydrogen fuels to support ventilation CFD analysis for specific enclosure designs. It is found that significantly smaller gas cloud sizes are likely to be acceptable for gas turbines fueled by hydrogen however significantly more hydrogen than methane is required per unit volume to generate a stoichiometric cloud (as hydrogen has a lower stoichiometric air fuel ratio than methane). This effect results in the total quantity of gas in the enclosure (and as such detectability of the gas) being broadly similar when operating gas turbines on hydrogen when compared to methane.

An opportunity to sequester large amounts of carbon dioxide (CO2) is made possible because hydraulic fracturing is used to produce most of America's natural gas. CO2 could be extracted from natural gas and water using steam methane reforming pressurized to its supercritical phase and used instead of water to fracture additional hydrocarbon-bearing rock. The useful energy carrier that remains is hydrogen with carbon returned to the ground. Research on the use of supercritical CO2 is reviewed with proppant entrainment identified as the major area where technical advances may be needed. The large potential for greenhouse-gas reduction through sequestration of CO2 and avoidance of methane leakage from the natural gas system is quantified.

With the decarbonization and electrification of modern railway transportation the demand for both the highcapacity electrical energy and hydrogen fuel energy is increasingly high. A novel scheme was proposed from liquid hydrogen production by surplus wind and solar energy to liquid hydrogen-electricity hybrid energy transmission for railway transportation. The 100 MW hybrid energy transmission pipeline was designed with the 10 kA/1.5 kV superconducting DC cable for electricity and cryogenic layers for liquid hydrogen and liquid nitrogen showing strong capability in transmitting “electricity + cold energy + chemical energy” simultaneously. Economic evaluation was performed with respect to the energy equipment capacity and costs with sensitivity and profitability analysis. With the discount rate 8% the dynamic payback period of the hybrid energy pipeline was 7.1 years. Results indicated that the shortest dynamic payback period of the hybrid energy pipeline was 4.8 years with the maximum transmission distance 93 km. Overall this article shows the novel concept and design of liquid hydrogen-electricity hybrid energy pipelines and proves the technical and economic feasibilities for future bulk hybrid energy transmission for railway transportation.

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

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

In order to maximise European national and regional research and innovation potential the European Union is investing in these fields through different funding mechanisms such as the ESIF or H2020 programme. This investment plan is part of the European 2020 strategy where the concept of Smart Specialisation is also included.<br/>Smart Specialisation is an innovation policy concept designed to promote the efficient and effective use of public investment in regional innovation in order to achieve economic growth. The Smart Specialisation Platform was created to support this concept by assisting regions and Member States in developing implementing and reviewing their research and innovation Smart Specialisation strategies.<br/>The Smart Specialisation Platform comprises several thematic platforms. The thematic Smart Specialisation Platform on energy (S3PEnergy) is a joint initiative of three European Commission services: DG REGIO DG ENER and the Joint Research Centre (JRC). The main objective of the S3PEnergy is to support the optimal and effective uptake of the Cohesion Policy funds for energy and to better align energy innovation activities at national local and regional level through the identification of the technologies and innovative solutions that support in the most cost-effective way the EU energy policy priorities.<br/>In the particular case of hydrogen technologies the activities of the platform are mainly focused on supporting the new Fuel Cells and Hydrogen Joint Undertaking (FCH JU) initiative involving regions and cities. To date more than 80 European cities and regions have committed to participate in this initiative through the signature of a Memorandum of Understanding and more participants are expected to join. S3PEnergy is helping in the identification of potential combination of H2020 funding (provided through FCH JU) and ESIF.<br/>To identify potential synergies among these two funding sources a mapping of the different ESIF opportunities has been performed. In order to map these opportunities Operational Programmes (OPs) and research and innovation strategies for Smart Specialisation (RIS3) of the different European regions and Member States were analysed. The results of this mapping and analysis are presented in this paper."

The hydrogen diffusion behavior and hydrogen embrittlement susceptibility of dual phase (DP) steels with different martensite content were investigated using the slow strain-rate tensile test and hydrogen permeation measurement. Results showed that a logarithmic relationship was established between the hydrogen embrittlement index (IHE) and the effective hydrogen diffusion coefficient (Deff). When the martensite content is low ferrite/ martensite interface behaves as the main trap that captures the hydrogen atoms. Also when the Deff decreases IHE increases with increasing martensite content. However when the martensite content reaches approximately 68.3% the martensite grains start to form a continuous network Deff reaches a plateau and IHE continues to increase. This is mainly related to the reduction of carbon content in martensite and the length of ferrite/martensite interface which promotes the diffusion of hydrogen atoms in martensite and the aggregation of hydrogen atoms at the ferrite/martensite interface. Finally a model describing the mechanism of microstructure-driven hydrogen diffusion with different martensite distribution was established.

This Supplement gives additional requirements and qualifications for the transmission of Hydrogen including Natural Gas/Hydrogen blended mixtures (subsequently referred to as NG/H blends) and for the repurposing of Natural Gas (NG) pipelines to Hydrogen service. For the purposes of this document any NG/H blend above 10% MOL is considered to be an equivalence to 100% hydrogen. For blends below 10% MOL there is no evidence to confirm that blends containing up to 10 mol.% hydrogen do not cause material degradation but it is considered that the risk is low.

This Supplement covers the design construction inspection testing operation and maintenance of steel pipelines and certain associated installations in Hydrogen service and the repurposing of NG pipelines to Hydrogen service at maximum operating pressure (MOP) exceeding 7 bar and not exceeding 137.9 bar.

This standard can be purchased here

Deep eutectic solvents (DES) are compounds of a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA) that contain a depressed melting point compared to their individual constituents. DES have been studied for their use as carbon capture media and biogas upgrading. However contaminants’ presence in biogas might affect the carbon capture by DES. In this study conductor-like screening model for real solvents (COSMO-RS) was used to determine the effect of temperature pressure and selective contaminants on five DES’ namely choline chloride-urea choline chloride-ethylene glycol tetra butyl ammonium chloride-ethylene glycol tetra butyl ammonium bromide-decanoic acid and tetra octyl ammonium chloride-decanoic acid. Impurities studied in this paper are hydrogen sulfide ammonia water nitrogen octamethyltrisiloxane and decamethylcyclopentasiloxane. At infinite dilution CO₂ solubility dependence upon temperature in each DES was examined by means of Henry’s Law constants. Next the systems were modeled from infinite dilution to equilibrium using the modified Raoults’ Law where CO₂ solubility dependence upon pressure was examined. Finally solubility of CO₂ and CH₄ in the various DES were explored with the presence of varying mole percent of selective contaminants. Among the parameters studied it was found that the HBD of the solvent is the most determinant factor for the effectiveness of CO₂ solubility. Other factors affecting the solubility are alkyl chain length of the HBA the associated halogen and the resulting polarity of the DES. It was also found that choline chloride-urea is the most selective to CO₂  but has the lowest CO₂ solubility and is the most polar among other solvents. On the other hand tetraoctylammonium chloride-decanoic acid is the least selective has the highest maximum CO₂ solubility is the least polar and is the least affected by its environment.

The use of hydrogen is expected to increase rapidly in the future. Leakage of hydrogen pipework are the main forms of safety problems in hydrogen utilization. In this paper a numerical model of hydrogen leakage and diffusion in pipe joints was established. The Schlieren + high-speed camera is used in experiments to observe the leakage of hydrogen in the pipe joints. In addition the shape and size of the scratches in the tube were statistically analyzed. Finally the leakage characteristics of double ferrule joints with scratches are experimentally analyzed. For the two scratch sizes the critical pressure values for the vortex transition are 0.2 MPa and 0.03 MPa. Through our experimental process some practical experience and suggestions are given.

Equinor has in recent years focused on low carbon technologies in addition to conventional oil & gas technologies. Clear strategic directions have been set to demonstrate Equinor’s commitment to longterm value creation that supports the Paris Agreement. This includes acceleration of decarbonization by establishing a well-functioning market for carbon capture transport and storage (CCS) as well as development of competitive hydrogen-based value chains and solutions. The specific properties of hydrogen must be taken into account in order to ensure safe design and operation of hydrogen systems as these properties differ substantially from those of natural gas and other conventional oil & gas products. Development projects need to consider and mitigate the increased possibility of high explosion pressures or detonation if hydrogen releases accumulate in enclosed or congested areas. On the other hand hydrogen’s buoyant properties can be exploited by locating potential leak points in the open to avoid gas accumulation thereby reducing the explosion risk. The purpose of this paper is to introduce Equinor’s hydrogen-based value chain projects and present our approach to ensure safe and effective designs. Safety strategies constitute the basis for Equinor’s safety and risk management. The safety strategies describe the connection between the hazards and risk profiles on one hand and the safety barrier elements and their needed performance on the other as input to safe design. The safety strategies also form the basis for safe operation. Measures to control the risk through practical designs follow from these strategies.

The aim of this paper is to analyze the factors affecting hydrogen and Carbon Capture and Storage Technologies (“CCS”) policies taking into consideration Fossil Fuel Consumption Oil Reserves the Debt/GDP Ratio the Trilemma Index and other variables with respect to OECD countries. STATA 17 was used for the analysis. The results confirm the hypothesis that countries with high fossil fuel consumption and oil reserves are investing in blue hydrogen and CCS towards a “zero-carbon-emission” perspective. Moreover countries with a good Debt/GDP ratio act most favorably to green policies by raising their Public Debt because Foreign Direct Investments are negatively correlated with those kinds of policies. Future research should exploit Green Finance policy decision criteria on green and blue hydrogen.

In recent times renewable energy systems (RESs) such as Photovoltaic (PV) and wind turbine (WT) are being employed to produce hydrogen. This paper aims to compare the efficiency and performance of PV and WT as sources of RESs to power polymer electrolyte membrane electrolyzer (PEMEL) under different conditions. The study assessed the input/ output power of PV and WT the efficiency of the MPPT controller the calculation of the green hydrogen production rate and the efficiency of each system separately. The study analyzed variable irradiance from 600 to 1000 W/m2 for a PV system and a fixed temperature of 25˚C while for the WT system it considered variable wind speed from 10 to 14 m/s and zero fixed pitch angle. The study demonstrated that the applied controllers were effective fast low computational and highly accurate. The obtained results showed that WT produces twice the PEMEL capacity while the PV system is designed to be equal to the PEMEL capacity. The study serves as a reference for designing PV or WT to feed an electrolyzer. The MATLAB program validated the proposed configurations with their control schemes.

Alongside our Sixth Carbon Budget Advice the Climate Change Committee (CCC) are publishing a paper from Professor Nick Chater the Committee’s behavioural science specialist. This paper considers three behavioural principles that explain how people have adapted so rapidly and how we might “build back better” as we emerge from the pandemic with a particular focus on meeting the challenge of dramatically reducing greenhouse gas (GHG) emissions over the coming decades. The principles are:

• The power law of practice: People organizations and whole industries learn to adapt to new ways of working following a surprisingly predictable pattern. This can help predict where adaptation to new ways of living and working is likely to succeed or fail.
• The status quo effect: People and organizations tend to prefer the current status quo but can often adjust rapidly to prefer a new status quo. However we tend to systematically underestimate such effects and therefore can sometimes resist changes that in retrospect we may ultimately prefer.
• Unwritten rules: Our social behaviour is guided by implicit guidelines about what is “appropriate” which can be somewhat independent of our personal values. Changing these implicit rules alongside changes in regulation and the law is crucial to adapting to new circumstances—and the pandemic has shown that rapid change is possible though sometimes resisted (e.g. new norms about mask wearing and social distancing).

This study uses an online quasi-experiment with a national sample from Australia to evaluate public acceptance of hydrogen exports. It explores the complex communications environment that messaging about hydrogen exports is typically encountered in. We find that acceptance of green hydrogen exports is significantly higher than blue or brown hydrogen exports and acceptance of blue hydrogen exports higher than brown hydrogen exports. Additionally results show economic-framed benefit messages are associated with lesser public acceptance when encountered in communication contexts that outline differently-focused environmental downsides (competing contexts) but not same-focused economic downsides (conflicting contexts). In contrast environment-framed benefit messages are associated with lesser public acceptance when presented in communication contexts that outline same-focused environmental downsides (conflicting contexts) but not differentlyfocused economic downsides (competing contexts). Overall the study indicates message framing can impact acceptance of hydrogen exports and that organisations should consider the informational context within which their communications will be received.

There is a large literature exploring possible hydrogen futures using various modelling and scenario approaches. This paper compares the rates of transition depicted in that literature with a set of historical analogies. These analogies are cases in which alternative-fuelled vehicles have penetrated vehicle markets. The paper suggests that the literature has tended to be optimistic about the possible rate at which hydrogen vehicles might replace oil-based transportation. The paper compares 11 historical adoptions of alternative fuel vehicles with 24 scenarios from 20 studies that depict possible hydrogen futures. All but one of the hydrogen scenarios show vehicle adoption faster than has occurred for hybrid electric vehicles in Japan the most successful market for hybrids. Several scenarios depict hydrogen transitions occurring at a rate faster than has occurred in any of the historic examples. The paper concludes that scenarios of alternative vehicle adoption should include more pessimistic scenarios alongside optimistic ones.