Norway

This article presents findings from a representative survey fielded through the Norwegian Citizen Panel examining public perceptions of hydrogen fuel and its different production methods. Although several countries including Norway have strategies to increase the production of hydrogen fuel our results indicate that hydrogen as an energy carrier and its different production methods are still unknown to a large part of the public. A common misunderstanding seems to be confusing ‘hydrogen fuel’ in general with environmentally friendly ‘green hydrogen’. Results from a survey experiment (N = 1906) show that production method is important for public acceptance. On a five-point acceptance scale respondents score on average 3.9 for ‘green’ hydrogen which is produced from renewable energy sources. The level of acceptance is significantly lower for ‘blue’ (3.2) and ‘grey’ (2.3) hydrogen when respondents are informed that these are produced from coal oil or natural gas. Public support for hydrogen fuel in general as well as the different production methods is also related to their level of worry about climate change gender and political affiliation. Widespread misunderstandings regarding ‘green’ hydrogen production could potentially fuel public resistance as new ‘blue’ or ‘grey’ projects develop. Our results indicate a need for clearer communication from the government and developers regarding production methods to avoid distrust and potential public backfire.

Hydrogen is expected to play a key role in the future as a clean energy source that can mitigate global warming. It can also contribute significantly to reducing the imbalance between energy supply and demand posed by deploying renewable energy. However the infrastructure is not ready for the direct use of hydrogen and largescale storage facilities are needed to store the excess hydrogen production. Geological formations particularly salt caverns seem to be a practical option for this large-scale storage as there is already good experience storing hydrocarbons in caverns worldwide. Salt is known to be ductile impermeable and inert to natural gas. Some cases of hydrogen storage in salt caverns in the United States the United Kingdom and Germany reinforce the idea that salt caverns could be a viable option for underground hydrogen storage especially when the challenges and uncertainties associated with hydrogen storage in porous media are considered. However cavern con struction and management can be challenging when salt deposits are not completely pure and mixed with nonsoluble strata. This review summarises the challenges associated with hydrogen storage in salt caverns and suggests some potential mitigation strategies linked to geomechanical and geochemical interactions. The Zechstein salt group in Northern Europe seems to be a feasible geological site for hydrogen storage but the effect of salt impurity particularly at deep offshore sites such as in the Norwegian North Sea should be carefully analysed. It appears that mechanical integrity geochemical reactions hydrogen loss by halophilic bacteria leaching issues and potential hydrogen diffusion are among the major issues when the internal structure of the salt is not pure.

Norwegian offshore wind farms may be able to supply power to offshore oil and gas platforms in the near future thanks to the expeditious development of offshore wind technology. This would result in a reduction in CO2 emissions from oil and gas offshore installations which are currently powered predominantly by gas turbines. The challenge with using wind power is that offshore oil and gas installations require a fairly constant and stable source of power whereas wind power typically exhibits significant fluctuations over time. The purpose of this study is to perform a technical feasibility evaluation of using wind power to supply an offshore oil and gas installation on the basis of dynamic process simulations. Throughout the study only the topside processing system is considered since it is the most energy-intensive part of an oil and gas facility. An offshore field on the Norwegian Continental Shelf is used as a case study. The results indicate that when the processing system operates in steady-state conditions it cannot be powered solely by wind energy and another power source is required to compensate for low wind power generation intervals. An alternative would be to store wind energy during periods of high generation (e.g. by producing hydrogen or ammonia) and use it during periods of low generation. Utilizing energy storage methods wind energy can be continuously used for longer periods of time and provide a suitable constant power source for the studied case. Higher constant power can also be provided by increasing the efficiency of energy recovery and storage processes. Alternatively these two technologies may be integrated with gas turbines if the required storage cannot be provided or higher power is required. It was estimated that the integration of wind energy could result in noticeable reductions in CO2 emissions for the case study. Additionally according to the results the production storage and reuse of hydrogen and ammonia on-site may be viable options for supplying power.

Anion exchange membrane water electrolysis (AEMWE) has acquired substantial consideration as a cost-effective hydrogen production technology. The anion ionomer content in the catalyst layers during hydrogen and oxygen evolution reaction (HER and OER) is of ultimate significance. Herein an in-situ half-cell analysis with reference electrodes was carried out for simultaneous potential measurements and identification of the influence of the anion exchange ionomer (AEI) content on anode and cathode performance. The measured half-cell potentials proved the influence of AEI content on the catalytic activity of HER and OER which was supported by the rotating disk electrode (RDE) measurements. Cathode overpotential of Ni/C was not negligible and more affected by the AEI content than anode with the optimized AEI content of 10 wt% while NiO anode OER overpotential was independent of the AEI content. For the same AEI content PGM catalysts showed higher electroactivity than Ni-based catalysts for HER and OER and the cathode catalyst's intrinsic activity is of high importance in the AEM electrolysis operation. Post-mortem analysis by SEM mapping of both AEI and catalyst distributions on the electrode surface showed the effect of AEI loading on the catalyst morphology which could be related to the electrode performance.

Palladium (Pd) membranes are a promising enabling technology for power generation and hydrogen production with CO2 capture. SINTEF has developed and patented a flexible technology to produce Pd-alloy membranes that significantly improves flux and thereby reduces material costs. Reinertsen AS and SINTEF aim to demonstrate the Pd membrane technology for H2 separation on a side stream of the Statoil Methanol Plant at Tjeldbergodden Norway. In the present article we present the upscaling of the membrane manufacturing process together with the membrane module and skid design and construction.

The hydrogen economy is currently experiencing a surge in attention partly due to the possibility of absorbing variable renewable energy (VRE) production peaks through electrolysis. A fundamental challenge with this approach is low utilization rates of various parts of the integrated electricity-hydrogen system. To assess the importance of capacity utilization this paper introduces a novel stylized numerical energy system model incorporating the major elements of electricity and hydrogen generation transmission and storage including both “green” hydrogen from electrolysis and “blue” hydrogen from natural gas reforming with CO₂ capture and storage (CCS). Concurrent optimization of all major system elements revealed that balancing VRE with electrolysis involves substantial additional costs beyond reduced electrolyzer capacity factors. Depending on the location of electrolyzers greater capital expenditures are also required for hydrogen pipelines and storage infrastructure (to handle intermittent hydrogen production) or electricity transmission networks (to transmit VRE peaks to electrolyzers). Blue hydrogen scenarios face similar constraints. High VRE shares impose low utilization rates of CO₂ capture transport and storage infrastructure for conventional CCS and of hydrogen transmission and storage infrastructure for a novel process (gas switching reforming) that enables flexible power and hydrogen production. In conclusion all major system elements must be considered to accurately reflect the costs of using hydrogen to integrate higher VRE shares.

Hydrogen is one of the most suitable solutions to replace hydrocarbons in the future. Hydrogen consumption is expected to grow in the next years. Hydrogen liquefaction is one of the processes that allows for increase of hydrogen density and it is suggested when a large amount of substance must be stored or transported. Despite being a clean fuel its chemical and physical properties often arise concerns about the safety of the hydrogen technologies. A potentially critical scenario for the liquid hydrogen (LH2) tanks is the catastrophic rupture causing a consequent boiling liquid expanding vapour explosion (BLEVE) with consequent overpressure fragments projection and eventually a fireball. In this work all the BLEVE consequence typologies are evaluated through theoretical and analytical models. These models are validated with the experimental results provided by the BMW care manufacturer safety tests conducted during the 1990’s. After the validation the most suitable methods are selected to perform a blind prediction study of the forthcoming LH2 BLEVE experiments of the Safe Hydrogen fuel handling and Use for Efficient Implementation (SH2IFT) project. The models drawbacks together with the uncertainties and the knowledge gap in LH2 physical explosions are highlighted. Finally future works on the modelling activity of the LH2 BLEVE are suggested.

Fully decarbonizing global industry is essential to achieving climate stabilization and reaching net zero greenhouse gas emissions by 2050–2070 is necessary to limit global warming to 2 °C. This paper assembles and evaluates technical and policy interventions both on the supply side and on the demand side. It identifies measures that employed together can achieve net zero industrial emissions in the required timeframe. Key supply-side technologies include energy efficiency (especially at the system level) carbon capture electrification and zero-carbon hydrogen as a heat source and chemical feedstock. There are also promising technologies specific to each of the three top-emitting industries: cement iron & steel and chemicals & plastics. These include cement admixtures and alternative chemistries several technological routes for zero-carbon steelmaking and novel chemical catalysts and separation technologies. Crucial demand-side approaches include material-efficient design reductions in material waste substituting low-carbon for high-carbon materials and circular economy interventions (such as improving product longevity reusability ease of refurbishment and recyclability). Strategic well-designed policy can accelerate innovation and provide incentives for technology deployment. High-value policies include carbon pricing with border adjustments or other price signals; robust government support for research development and deployment; and energy efficiency or emissions standards. These core policies should be supported by labeling and government procurement of low-carbon products data collection and disclosure requirements and recycling incentives. In implementing these policies care must be taken to ensure a just transition for displaced workers and affected communities. Similarly decarbonization must complement the human and economic development of low- and middle-income countries.

Governments and other stakeholders actively promote and facilitate the development and deployment of hydrogen and fuel cell technologies. Various strategy documents and energy forecasts outline the environmental and societal benefits of the prospective hydrogen economy. At the same time the safety related properties of hydrogen imply that it is not straightforward to achieve and document the same level of safety for hydrogen systems compared to conventional fuels. Severe accidents can have major impact on the development of energy technologies. The stakes will increase significantly as the use of hydrogen shifts from controlled environments in industrial facilities to the public domain and as the transport-related consumption extends from passenger cars and buses to trains ships and airplanes. Widespread deployment of hydrogen as an energy carrier in society will require massive investments. This implies commercial and political commitment involvement and influence on research priorities and decision-making. The legacy from accidents and the messages communicated by influential stakeholders impact not only how the public perceives hydrogen technologies but also governmental policies the development of regulations codes and standards (RCS) and ultimately the measures adopted for preventing and mitigating accidents. This paper explores whether and how selected aspects of safety are considered when distinct groups of stakeholders frame the hydrogen economy. We assess to what extent the communication is consistent with the current state-of-the-art in hydrogen safety and the contemporary strength of knowledge in risk assessments for hydrogen systems. The approach adopted entails semi-quantitative text analysis and close reading to highlight variations between diverse groups of stakeholders. The results indicate a bias in the framing of the safety-related aspects of the hydrogen economy towards procedural organisational and societal measures of risk reduction at the expense of well-known challenges and knowledge gaps associated with the implications of fundamental safety-related properties of hydrogen.

Carbon efficiency of a biomass to liquid process can be increased from ca. 30 to more than 90% by adding hydrogen generated from renewable power. The main reason is that in order to increase the H2/CO ratio after gasification to the value required for Fischer-Tropsch (FT) synthesis the water gas shift reaction step can be avoided; instead a reversed water gas shift reactor is introduced to convert produced CO2 to CO. Process simulations are done for a 46 t/h FT biofuel production unit. Previous results are confirmed and it is shown how the process can be further improved. The effect of changing the H2/CO ratio to the Fischer-Tropsch synthesis reactors is studied with the use of three different kinetic models. Keeping the CO conversion in the reactors constant at 55% the volume of the reactors decreases with increasing H2/CO ratio because the reaction rates increase with the partial pressure of hydrogen. Concurrently the production of C5+ products and the consumption of hydrogen increases. However the power required per extra produced liter fuel also increases pointing at optimum conditions at a H2/CO feed ratio significantly lower than 2. The trends are the same for all three kinetic models although one of the models is less sensitive to the hydrogen partial pressure. Finally excess renewable energy can be transformed to FT syncrude with an efficiency of 0.8–0.88 on energy basis.

‘E-fuels’ or ‘synthetic fuels’ are hydrocarbon fuels synthesized from hydrogen (H2) and carbon dioxide (CO2) where H2 can be produced via electrolysis of water or steam reforming of natural gas and CO2 is captured from the combustion of a fossil or biogenic source or directly from the atmosphere. E-fuels are drop-in substitutes for fossil fuels but their climate change mitigation benefits are largely unclear. This study evaluates the climate change impacts of e-fuels for aviation by combining different sources of CO2 and H2 up to 2050 under two contrasting policy scenarios. The analysis includes different climate metrics and the effects of near-term climate forcers which are particularly relevant for the aviation sector. Results are produced for European average conditions and for Poland and Norway two countries with high and low emission intensity from their electricity production mix. E-fuels can either have higher or lower climate change impacts than fossil fuels depending on multiple factors such as in order of importance the electricity mix the origin of CO2 the technology for H2 production and the electrolyzer efficiency. The climate benefits are generally higher for e-fuels produced from CO2 of biogenic origin while e-fuels produced from CO2 from direct air capture or fossil fuel combustion require countries with clean electricity to outperform fossil fuels. Synthetic fuels produced from H2 derived from natural gas have higher impacts than fossil fuels even when coupled with carbon capture and storage if CO2 is sourced from fossil fuels or the atmosphere. Climate change impacts of e-fuels improve in the future and they can all achieve considerable climate change mitigation in 2050 relative to fossil jet fuel provided that strict climate policy measures are implemented to decarbonize the electricity sector. Under reduced policy efforts future climate impacts in 2050 of e-fuels from atmospheric or fossil CO2 are still higher than those of fossil jet fuels with an average European electricity mix. This study shows the conditions to maximize the climate change mitigation benefits of e-fuels which essentially depend on progressive decarbonization of the electricity sector and on reduced use of CO2 sourced from fossil fuels.

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.

Automotive proton-exchange membrane fuel cells (PEMFCs) have finally reached a state of technological readiness where several major automotive companies are commercially leasing and selling fuel cell electric vehicles including Toyota Honda and Hyundai. These now claim vehicle speed and acceleration refueling time driving range and durability that rival conventional internal combustion engines and in most cases outperform battery electric vehicles. The residual challenges and areas of improvement which remain for PEMFCs are performance at high current density durability and cost. These are expected to be resolved over the coming decade while hydrogen infrastructure needs to become widely available. Here we briefly discuss the status of automotive PEMFCs misconceptions about the barriers that platinum usage creates and the remaining hurdles for the technology to become broadly accepted and implemented.

For many a large-scale hydrogen economy is essential to a a clean energy future with three quarters of the more than 1100 senior energy professionals we surveyed saying Paris Agreement targets will not be possible without it.

DNV’s research Rising to the challenge of a hydrogen economy explores the outlook for emerging hydrogen value chains from production to consumption. It combines the wider view from the energy industry with commentary from business leaders and experts. Our research finds that the challenge is not in the ambition but in changing the timeline: from hydrogen on the horizon to hydrogen in our homes businesses and transport systems.

We see that the energy industry is rising to this challenge. By 2025 almost half (44%) of energy companies globally involved in hydrogen expect it to account for more than a tenth of their revenue rising to 73% of companies by 2030 – up significantly from just 8% of companies today. The research identifies infrastructure and cost as two of the biggest hurdles while the right regulations are deemed the most powerful enabler followed by carbon pricing. Proving the safety case will also be key to scaling the hydrogen economy.

Download your complimentary copy of DNV’s latest hydrogen research at their website link

Proton exchange membrane (PEM) electrolysers (PEMEL) are key for converting and storing excess renewable energy. PEMEL water electrolysis offers benefits over alkaline water electrolysers including a large dynamic range high responsiveness and high current densities and pressures. High operating pressures are important because it contributes to reduce the costs and energy-use related to downstream mechanical compression. In this work the performance of a high-pressure PEMEL system has been characterized up to 180 bar. The electrolyser stack has been characterized with respect to electrochemical performance net H2 production rate and water crossover and the operability and performance of the thermal- and gas management systems of the test bench has been assessed. The tests show that the voltage increase upon pressurization from 5 to 30 bar is 30 % smaller than expected but further pressurization reduces performance. The study confirms that highpressure PEMEL has higher energy consumption than state-of-the-art electrolyser systems with mechanical compressors. However there can be a business case for high-pressure PEMEL if the trade-off between stack efficiency and system efficiency is balanced.

Throughout the history of the mining petroleum process and nuclear industries continuous efforts have been made to develop and improve measures to prevent and mitigate accidental explosions. Over the coming decades energy systems are expected to undergo a transition towards sustainable use of conventional hydrocarbons and an increasing share of renewable energy sources in the global energy mix. The variable and intermittent supply of energy from solar and wind points to energy systems based on hydrogen or hydrogen-based fuels as the primary energy carriers. However the safety-related properties of hydrogen imply that it is not straightforward to achieve and document the same level of safety for hydrogen systems compared to similar systems based on established fuels such as petrol diesel and natural gas. Compared to the conventional fuels hydrogen-air mixtures have lower ignition energy higher combustion reactivity and a propensity to undergo deflagration-to-detonation-transition (DDT) under certain conditions. To achieve an acceptable level of safety it is essential to develop effective measures for mitigating the consequences of hydrogen explosions in systems with certain degree of congestion and confinement. Extensive research over the last decade have demonstrated that chemical inhibition or partial suppression can be used for mitigating the consequences of vapour cloud explosions (VCEs) in congested process plants. Total and cooperation partners have demonstrated that solid flame inhibitors injected into flammable hydrocarbon-air clouds represent an effective means of mitigating the consequences of VCEs involving hydrocarbons. For hydrogen-air explosions these same chemicals inhibitors have not proved effective. It is however well-known that hydrocarbons can affect the burning velocity of hydrogen-air mixtures greatly. This paper gives an overview over previous work on chemical inhibitors. In addition experiments in a 20-litre vessel have been performed to investigate the effect of combinations of hydrocarbons and alkali salts on hydrogen/air mixtures.

This paper is a critical review of selected real-world energy storage systems based on hydrogen ranging from lab-scale systems to full-scale systems in continuous operation. 15 projects are presented with a critical overview of their concept and performance. A review of research related to power electronics control systems and energy management strategies has been added to integrate the findings with outlooks usually described in separate literature. Results show that while hydrogen energy storage systems are technically feasible they still require large cost reductions to become commercially attractive. A challenge that affects the cost per unit of energy is the low energy efficiency of some of the system components in real-world operating conditions. Due to losses in the conversion and storage processes hydrogen energy storage systems lose anywhere between 60 and 85% of the incoming electricity with current technology. However there are currently very few alternatives for long-term storage of electricity in power systems so the interest in hydrogen for this application remains high from both industry and academia. Additionally it is expected that the share of intermittent renewable energy in power systems will increase in the coming decades. This could lead to technology development and cost reductions within hydrogen technology if this technology is needed to store excess renewable energy. Results from the reviewed projects indicate that the best solution from a technical viewpoint consists in hybrid systems where hydrogen is combined with short-term energy storage technologies like batteries and supercapacitors. In these hybrid systems the advantages with each storage technology can be fully exploited to maximize efficiency if the system is specifically tailored to the given situation. The disadvantage is that this will obviously increase the complexity and total cost of the energy system.<br/>Therefore control systems and energy management strategies are important factors to achieve optimal results both in terms of efficiency and cost. By considering the reviewed projects and evaluating operation modes and control systems new hybrid energy systems could be tailored to fit each situation and to reduce energy losses.

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 Pressure Peaking Phenomena (PPP) is the effect of introducing a light gas into a vented volume of denser gas. This will result in a nonequilibrium pressure as the light gas pushes the dense gas out at the vent. Large scale experiments have been performed to produce relevant evidence. The results were used to validate an analytical model. Pressure and temperature were measured inside a constant volume while the mass flow and vent area were varied. The analytical model was based on the conservation of mass and energy. The results showed that increasing the mass flow rate the peak pressure increases and with increasing the ventilation area the peak pressure decreases. Peak pressure was measured above 45 kPa. Longer combustion time resulted in higher temperatures increasing an underpressure effect. The experimental results showed agreement with the analytical model results. The model predicts the pressures within reasonable limits of+/-2 kPa. The pressure peaking phenomena could be very relevant for hydrogen applications in enclosures with limited ventilation. This could include car garages ship hull compartments as well as compressor shielding. This work shows that the effect can be modeled and results can be used in design to reduce the consequences.

Hydrogen is a valuable option of clean fuel to keep the global temperature rise below 2°C. However one of the main barriers in its transport and use is to ensure safety levels that are comparable with traditional fuels. In particular liquid hydrogen accidents may not be fully understood (yet) and excluded by relevant risk assessment. For instance as hydrogen is cryogenically liquefied to increase its energy density during transport Boiling Liquid Expanding Vapor Explosions (BLEVE) is a potential and critical event that is important addressing in the hazard identification phase. Two past BLEVE accidents involving liquid hydrogen support such thesis. For this reason results from consequence analysis of hydrogen BLEVE will not only improve the understanding of the related physical phenomenon but also influence future risk assessment studies. This study aims to show the extent of consequence analysis influence on overall quantitative risk assessment of hydrogen technologies and propose a systematic approach for integration of overall results. The Dynamic Procedure for Atypical Scenario Identification (DyPASI) is used for this purpose. The work specifically focuses on consequence models that are originally developed for other substances and adapted for liquid hydrogen. Particular attention is given to the parameters affecting the magnitude of the accident as currently investigated by a number of research projects on hydrogen safety worldwide. A representative example of consequence analysis for liquid hydrogen release is employed in this study. Critical conditions detected by the numerical simulation models are accurately identified and considered for subsequent update of the overall system risk assessment.

While the effects of ongoing cost reductions in renewables batteries and electrolyzers on future energy systems have been extensively investigated the effects of significant advances in CO2 capture and storage (CCS) technologies have received much less attention. This research gap is addressed via a long-term (2050) energy system model loosely based on Germany yielding four main findings. First CCS-enabled pathways offer the greatest benefits in the hydrogen sector where hydrogen prices can be reduced by two-thirds relative to a scenario without CCS. Second advanced blue hydrogen technologies can reduce total system costs by 12% and enable negative CO2 emissions due to higher efficiencies and CO2 capture ratios. Third co-gasification of coal and biomass emerged as an important enabler of these promising results allowing efficient exploitation of limited biomass resources to achieve negative emissions and limit the dependence on imported natural gas. Finally CCS decarbonization pathways can practically and economically incorporate substantial shares of renewable energy to reduce fossil fuel dependence. Such diversification of primary energy inputs increases system resilience to the broad range of socio-techno-economic challenges facing the energy transition. In conclusion balanced blue-green pathways offer many benefits and deserve serious consideration in the global decarbonization effort.

Implementation of the hydrogen economy for emission reduction will require storage facilitiesand underground hydrogen storage (UHS) in porous media offers a readily available large-scale option. Lack ofstudies on multiphase hydrogen flow in porous media is one of the several barriers for accurate predictions ofUHS. This paper reports for the first time measurements of hysteresis in hydrogen-water relative permeabilityin a sandstone core under shallow storage conditions. We use the steady state technique to measure primarydrainage imbibition and secondary drainage relative permeabilities and extend laboratory measurements withnumerical history matching and capillary pressure measurements to cover the whole mobile saturation range.We observe that gas and water relative permeabilities show strong hysteresis and nitrogen as substitute forhydrogen in laboratory assessments should be used with care. Our results serve as calibrated input to field scalenumerical modeling of hydrogen injection and withdrawal processes during porous media UHS.

This paper presents a series of experiments on the effectiveness of existing mechanical ventilation systems during accidental hydrogen releases in confined spaces like underground garages. The purpose was to find the mass flow rate limit hence the TPRD diameter limit that will not require a change in the ventilation system. The experiments were performed in a 40 ft ISO container in Norway and hydrogen gas was used in all experiments. The forced ventilation system was installed with a standard outlet 315 mm diameter. The ventilation parameters during the investigation were British Standard with 10 ACH and British Standard with 6 ACH. The hydrogen releases were obtained through 0.5 mm and 1 mm nozzle from different hydrogen reservoir pressures. Both types of mass flow: constant and blowdown were included in the experimental matrix. The analysis of hydrogen concentration of created hydrogen cloud in the container shows the influence of the forced ventilation on hydrogen releases together with TPRD diameter and reservoir pressure. The generated experimental data will be used to validate a CFD model in the next step.

Rapidly declining costs of renewable energy technologies have made solar and wind the cheapest sources of energy in many parts of the world. This has been seen primarily as enabling the rapid decarbonization of the electricity sector but low-cost low-carbon energy can have a great secondary impact by reducing the costs of energy-intensive decarbonization efforts in other areas. In this study we consider by way of an exemplary carbon capture and utilization cycle based on mature technologies the energy requirements of the “industrial carbon cycle” an emerging paradigm in which industrial CO2 emissions are captured and reprocessed into chemicals and fuels and we assess the impact of declining renewable energy costs on overall economics of these processes. In our exemplary process CO2 is captured from a cement production facility via an amine scrubbing process and combined with hydrogen produced by a solar-powered polymer electrolyte membrane using electrolysis to produce methanol. We show that solar heat and electricity generation costs currently realized in the Middle East lead to a large reduction in the cost of this process relative to baseline assumptions found in published literature and extrapolation of current energy price trends into the near future would bring costs down to the level of current fossil-fuel-based processes.

This paper describes two models for analysing and simulating the physical effects of explosive phase transition of liquid hydrogen (LH2) also known as cold BLEVE. The present work is based on theoretical and experimental work for liquefied CO2. A Rankine Hugoniot analysis for evaporation waves that was previously developed for CO2 is now extended to LH2. A CFD-method for simulating two-phase flow with mass transfer between the phases is presented and compared with the Rankine Hugoniot analysis results. The Rankine Hugoniot method uses real fluid equations of state suited for LH2 while the CFD method uses linear equations of state suited for shock capturing methods. The results show that there will be a blast from a catastrophic rupture of an LH2 vessel and that the blast waves will experience a slow decay due to the large positive pressure phase.