Germany

The global trend towards decarbonization and the demand for energy security have put hydrogen energy into the spotlight of industry politics and societies. Numerous governments worldwide are adopting policies and strategies to facilitate the transition towards hydrogen-based economies. To assess the determinants of such transition this study presents a comparative analysis of the technological innovation systems (TISs) for hydrogen technologies in Germany and South Korea both recognized as global front-runners in advancing and implementing hydrogen-based solutions. By providing a multi-dimensional assessment of pathways to the hydrogen economy our analysis introduces two novel and crucial elements to the TIS analysis: (i) We integrate the concept of ‘quality infrastructure’ given the relevance of safety and quality assurance for technology adoption and social acceptance and (ii) we emphasize the social perspective within the hydrogen TIS. To this end we conducted 24 semi-structured expert interviews applying qualitative open coding to analyze the data. Our results indicate that the hydrogen TISs in both countries have undergone significant developments across various dimensions. However several barriers still hinder the further realization of a hydrogen economy. Based on our findings we propose policy implications that can facilitate informed policy decisions for a successful hydrogen transition.

Is there a place for today’s fossil fuel exporters in a low-carbon future? This study explores trade channels between energy exporters and importers using a novel electricity-hydrogen-steel energy systems model calibrated to Norway a major natural gas producer and Germany a major energy consumer. Under tight emission constraints Norway can supply Germany with electricity (blue) hydrogen or natural gas with re-import of captured CO2. Alternatively it can use hydrogen to produce steel through direct reduction and supply it to the world market an export route not available to other energy carriers due to high transport costs. Although results show that natural gas imports with CO2 capture in Germany is the least-cost solution avoiding local CO2 handling via imports of blue hydrogen (direct or embodied in steel) involves only moderately higher costs. A robust hydrogen demand would allow Norway to profitably export all its natural gas production as blue hydrogen. However diversification into local steel production as one example of easy-to-export industrial base products offers an effective hedge against the possibility of lower European blue hydrogen demand. Looking beyond Europe the findings of this study are also relevant for the world’s largest energy exporters (e.g. OPEC+) and importers (e.g. developing Asia). Thus it is recommended that large hydrocarbon exporters consider a strategic energy export transition to a diversified mix of blue hydrogen and climate-neutral industrial base products.

Salt caverns have great potential to store relevant amounts of hydrogen as part of the energy transition. However the durability and suitability of commonly used steels for piping in hydrogen salt caverns is still under research. In this work aging effects focusing on corrosion and cracking patterns of casing steel API 5CT J55 and “H2ready” pipeline steel API 5L X56 were investigated with scanning electron microscopy and energy dispersive X-ray spectroscopy after accelerated stress tests with pressure/temperature cycling under hydrogen salt cavern-like conditions. Compared to dry conditions significant more corrosion by presence of salt ions was detected. However compared to X56 only for J55 an intensification of corrosion and cracking at the surface due to hydrogen atmosphere was revealed. Pronounced surface cracks were observed for J55 over the entire samples. Overall the results strongly suggest that X56 is more resistant than J55 under the conditions of a hydrogen salt cavern.

A growing share of renewable energy production in the energy supply systems is key to reaching the European political goal of zero CO2 emission in 2050 highlighted in the green deal. Linked to the irregular production of solar and wind energies which have the highest potential for development in Europe massive energy storage solutions are needed as energy buffers. The European project HyPSTER [1] (Hydrogen Pilot STorage for large Ecosystem Replication) granted by the Clean Hydrogen Partnership addresses this topic by demonstrating a cyclic test in an experimental salt cavern filled with hydrogen up to 3 tons using hydrogen that is produced onsite by a 1 MW electrolyser. One specific objective of the project is the assessment of the risks and environmental impacts of cyclic hydrogen storage in salt caverns and providing guidelines for safety regulations and standards. This paper highlights the first outcome of the task WP5.5 of the HyPSTER project addressing the regulatory and normative frameworks for the safety of hydrogen storage in salt caverns from some selected European Countries which is dedicated to defining recommendations for promoting the safe development of this industry within Europe.

Desulphurization of oil-based fuels is common practice to mitigate the ecological burden to ecosystems and human health of SOx emissions. In many countries fuels for vehicles are restricted to 10 ppm sulphur. For marine fuels low sulphur contents are under discussion. The environmental impact of desulphurization processes is however quite high: (1) The main current source for industrial hydrogen is Steam Methane Reforming (SMR) with a rather high level of CO2 emissions (2) the hydrotreating process especially below 150 ppm needs a lot of energy. These two issues lead to three research questions: (a) What is the overall net ecological benefit of the current desulphurization practice? (b) At which sulfphur ppm level in the fuel is the additional ecological burden of desulphurization higher than the additional ecological benefit of less SOx pollution from combustion? (c) To what extent can cleaner hydrogen processes improve the ecological benefit of diesel desulphurization? In this paper we use LCA to analyze the processes of hydrotreatment the recovery of sulphur via amine treating of H2S and three processes of hydrogen production: SMR without Carbon Capture and Sequestration (CCS) SMR with 53% and 90% CCS and water electrolysis with two types of renewable energy. The prevention-based eco-costs system is used for the overall comparison of the ecological burden and the ecological benefit. The ReCiPe system was applied as well but appeared not suitable for such a comparison (other damage-based indicators cannot be applied either). The overall conclusion is that (1) the overall net ecological benefit of hydrogen-based Ultra Low Sulphur Diesel is dependent of local conditions but is remarkably high (2) desulphurization below 10 ppm is beneficial for big cities and (3) cleaner production of hydrogen reduces eco-cost by a factor 1.8–3.4.

A real-time on-site monitoring of the concentration of hydrogen and the heating value of a blend of hydrogen and natural gas is of key importance for its safe distribution in existing pipelines as proposed by the ‘Power-toGas’ concept. Although current gas chromatography (PGC) methods deliver this information accurately they are unsuitable for a quick and pipelineintegrated measurement. We analyse the possibility to monitor this blend with a combination of sensors of thermodynamic properties—thermal conductivity speed of sound and density—as a potential substitute for PGC. We propose a numerical method for this multi-sensor detection based on the assumption of ideal gas (i.e. low-pressure) behaviour treating natural gas as a ‘mixture of mixtures’ depending on how many geographical sources are drawn upon for its distribution. By performing a Monte-Carlo simulation with known concentrations of natural gas proceeding from different European sources we conclude that the combined measurement of thermal conductivity together with either speed of sound or density can yield a good estimation of both variables of interest (hydrogen concentration and heating value) even under variability in the composition of natural gas.

The EU Horizon2020 RISE project 778307 “Hydrogen fuelled utility and their support systems utilising metal hydrides” (HYDRIDE4MOBILITY) worked on the commercialization of hydrogen powered forklifts using metal hydride (MH) based hydrogen stores. The project consortium joined forces of 9 academic and industrial partners from 4 countries. The work program included a) Development of the materials for hydrogen storage and compression; b) Theoretical modelling and optimisation of the materials performance and system integration; c) Advanced fibre reinforced composite cylinder systems for H2 storage and compression; d) System validation. Materials development was focused on i) Zr/Ti-based Laves type high entropy alloys; ii) Mg-rich composite materials; iii) REMNiSn intermetallics; iv) Mg based materials for the hydrolysis process; v) Cost-efficient alloys. For the optimized AB2±x alloys the Zr/Ti content was optimized at A = Zr78-88Ti12–22 while B=Ni10Mn5.83VFe. These alloys provided a) Low hysteresis of hydrogen absorption-desorption; b) Excellent kinetics of charge and discharge; c) Tailored thermodynamics; d) Long cycle life. Zr0.85Ti0.15TM2 alloy provided a reversible H storage and electrochemical capacity of 1.6 wt% H and 450 mAh/g. The tanks development targeted: i) High efficiency of heat and hydrogen exchange; ii) Reduction of the weight and increasing the working H2 pressure; iii) Modelling testing and optimizing the H2 stores with fast performance. The system for power generation was validated at the Implats plant in a fuel cell powered forklift with on-board MH hydrogen storage and on-site H2 refuelling. The outcome on the HYDRIDE4MOBILITY project (2017–2024) (http://hydride4mobility.fesb.unist. hr) was presented in 58 publications.

An important element of modern firefighting is sometimes the use of foam. After the use of extinguishing foam on vehicles or machinery operated by compressed gases it is conceivable that masses of foam were enriched by escaping fuel gas. Furthermore new foam creation enriched with a high level of fuel gas from the deposed foam solution becomes theoretically possible. The aim of this study was to carry out basic experimental investigations on the combustion of water-based H2/air foam. Ignition tests were carried out in a transparent and vertically oriented cylindrical tube (d = 0.09 m; 1.5 m length) and a rectangular thin layer channel (0.02 m × 0.2 m; 2 m length). Additionally results from larger scale tests performed inside a pool (0.30 m × 1 m × 2 m) are presented. All ducts are semi-confined and a foam generator fills the ducts from below with the defined foam. The foams vary in type and concentration of the foaming agent and hydrogen concentration. The expansion ratio of the combustible foam is in the range of 20 to 50 and the investigated H2-concentrations vary from 8 to 70% H2 in air. High-speed imaging is used to observe the combustion and determine flame velocities. The study shows that foam is flammable over a wide range of H2-concentrations from 9 to 65% H2 in air. For certain H2/air-mixtures an abrupt flame acceleration is observed. The velocity of combustion increases rapidly by an order of magnitude and reaches velocities of up to 80 m/s.

Ammonia a molecule that is gaining more interest as a fueling vector has been considered as a candidate to power transport produce energy and support heating applications for decades. However the particular characteristics of the molecule always made it a chemical with low if any benefit once compared to conventional fossil fuels. Still the current need to decarbonize our economy makes the search of new methods crucial to use chemicals such as ammonia that can be produced and employed without incurring in the emission of carbon oxides. Therefore current efforts in this field are leading scientists industries and governments to seriously invest efforts in the development of holistic solutions capable of making ammonia a viable fuel for the transition toward a clean future. On that basis this review has approached the subject gathering inputs from scientists actively working on the topic. The review starts from the importance of ammonia as an energy vector moving through all of the steps in the production distribution utilization safety legal considerations and economic aspects of the use of such a molecule to support the future energy mix. Fundamentals of combustion and practical cases for the recovery of energy of ammonia are also addressed thus providing a complete view of what potentially could become a vector of crucial importance to the mitigation of carbon emissions. Different from other works this review seeks to provide a holistic perspective of ammonia as a chemical that presents benefits and constraints for storing energy from sustainable sources. State-of-the-art knowledge provided by academics actively engaged with the topic at various fronts also enables a clear vision of the progress in each of the branches of ammonia as an energy carrier. Further the fundamental boundaries of the use of the molecule are expanded to real technical issues for all potential technologies capable of using it for energy purposes legal barriers that will be faced to achieve its deployment safety and environmental considerations that impose a critical aspect for acceptance and wellbeing and economic implications for the use of ammonia across all aspects approached for the production and implementation of this chemical as a fueling source. Herein this work sets the principles research practicalities and future views of a transition toward a future where ammonia will be a major energy player.

While hydrogen is regularly discussed as a possible option for storing regenerative energies its low minimum ignition energy and broad range of explosive concentrations pose safety challenges regarding hydrogen storage and there are also challenges related to hydrogen production and transport and at the point of use. A risk assessment of the whole hydrogen energy system is necessary to develop hydrogen utilization further. Here we concentrate on the most important hydrogen storage technologies especially high-pressure storage liquid hydrogen in cryogenic tanks methanol storage and salt cavern storage. This review aims to study the most recent research results related to these storage techniques by describing typical sensors and explosion protection measures thus allowing for a risk assessment of hydrogen storage through these technologies.