Germany

The current energy system is subject to a fundamental transformation: A system that is oriented towards a constant energy supply by means of fossil fuels is now expected to integrate increasing amounts of renewable energy to achieve overall a more sustainable energy supply. The challenges arising from this paradigm shift are currently most obvious in the area of electric power supply. However it affects all areas of the energy system albeit with different results. Within the energy system various independent grids fulfill the function of transporting and spatially distributing energy or energy carriers and the demand-oriented supply ensures that energy demands are met at all times. However renewable energy sources generally supply their energy independently from any specific energy demand. Their contribution to the overall energy system is expected to increase significantly.<br/>Energy storage technologies are one option for temporal matching of energy supply and demand. Energy storage systems have the ability to take up a certain amount of energy store it in a storage medium for a suitable period of time and release it in a controlled manner after a certain time delay. Energy storage systems can also be constructed as process chains by combining unit operations each of which cover different aspects of these functions. Large-scale mechanical storage of electric power is currently almost exclusively achieved by pumped-storage hydroelectric power stations.<br/>These systems may be supplemented in the future by compressed-air energy storage and possibly air separation plants. In the area of electrochemical storage various technologies are currently in various stages of research development and demonstration of their suitability for large-scale electrical energy storage. Thermal energy storage technologies are based on the storage of sensible heat exploitation of phase transitions adsorption/desorption processes and chemical reactions. The latter offer the possibility of permanent and loss-free storage of heat. The storage of energy in chemical bonds involves compounds that can act as energy carriers or as chemical feedstocks. Thus they are in direct economic competition with established (fossil fuel) supply routes. The key technology here – now and for the foreseeable future – is the electrolysis of water to produce hydrogen and oxygen.<br/>Hydrogen can be transformed by various processes into other energy carriers which can be exploited in different sectors of the energy system and/or as raw materials for energy-intensive industrial processes. Some functions of energy storage systems can be taken over by industrial processes. Within the overall energy system chemical energy storage technologies open up opportunities to link and interweave the various energy streams and sectors. Chemical energy storage not only offers means for greater integration of renewable energy outside the electric power sector it also creates new opportunities for increased flexibility novel synergies and additional optimization.<br/>Several examples of specific energy utilization are discussed and evaluated with respect to energy storage applications. The article describes various technologies for energy storage and their potential applications in the context of Germany’s Energiewende i.e. the transition towards a more sustainable energy system. Therefore the existing legal framework defines some of the discussions and findings within the article specifically the compensation for renewable electricity providers defined by the German Renewable Energy Sources Act which is under constant reformation. While the article is written from a German perspective the authors hope this article will be of general interest for anyone working in the areas of energy systems or energy technology.

A series of experiments on hydrogen flame propagation in a thin layer geometry is presented. Premixed hydrogen-air compositions in the range from 6 to 15%(vol.) H2 are tested. Semi-open vertical combustion chamber consists of two transparent Plexiglas side walls with main dimensions of 90x20 cm with a gap from 1 to 10 mm in between. Test mixtures are ignited at the open end of the chamber so that the flame propagates towards the closed end. Ignition position changes from top to bottom in order to take into account an effect of gravity on flame propagation regimes. High-speed shadow imaging is used to visualize and record the combustion process. Thermal-diffusion and Darrieus-Landau instabilities are governing the general flame behaviour. Heat losses to side walls and viscous friction in a thin layer may fully suppress the flame propagation with local or global extinction. The sensitivity to heat losses can be characterized using a Peclet number as a ratio of layer thickness to laminar flame thickness. Approaching to critical Peclet number Pec = 42 the planar or wrinkled flame surface degradants to one-or two-heads "finger" flame propagating straight (for two-heads flame) or chaotic (for one-head "finger" flame). Such a "fingering" of the flame is found for the first time for gaseous systems and very similar to that reported for smouldering or filtering combustion of solid materials and also under micro-gravity conditions. The distance between "fingers" may depend on deficit of limiting component. The processes investigated can be very important from academic and practical points of view with respect to safety of hydrogen fuel cells.

A hydrogen purification system based on the technology of the electrochemical hydrogen compression and purification is introduced. This system is developed within the scope of the project MEMPHYS. Therefore the project its targets and the different work stages are presented. The technology of the electrochemical purification and the state of the art of hydrogen purification are described. Early measurements in the project have been carried out and the results are shown and discussed. The ability of the technology to recover hydrogen from a gas mixture can be recognized and an outlook into further optimizations shows the future potential. A big advantage is the simultaneous compression of the purified hydrogen up to 200 bar therefore facilitating the transportation and storage.

Growing demand for individual and especially complex parts with emphasis on biomedical or lightweight applications enhances the importance of laser powder bed fusion. Magnesium alloys offer both biocompatibility and low density but feature a very high melting point of oxide layers while the evaporation temperature of pure magnesium is much lower. This impedes adequate part quality and process reproducibility. To weaken this oxide layer and enhance processability a 2 %-hydrogen-argon-gas atmosphere was investigated. A machine system was modified to the use of the novel inert gas to determine the influence of gas atmosphere on hollow cuboids and solid cubes. While processing a 20.3 % decrease in structure width and 20.6 % reduction in standard deviation of the cuboids was determined. There was no significate influence on relative density of solid cubes although eight of the ten highest density specimen were fabricated with the hydrogen addition.

The energy transition – which represents the efforts undertaken and results achieved on renewable energy expansion and energy efficiency – is our basis for a clean secure and affordable energy supply which is essential for all our lives. By adopting the 2030 Climate Action Plan the Federal Government has paved the way for meeting its climate targets for 2030. Its long-term goal is to achieve carbon neutrality in line with the targets agreed under the Paris Agreement which seeks to keep global warming well below 2 degrees and if possible below 1.5 degrees. In addition Germany has committed itself together with the other European Member States to achieving greenhouse gas (GHG) neutrality by 2050. Apart from phasing out coal-fired power for which Germany has already taken the relevant decisions this means preventing emissions which are particularly hard to reduce such as process-related GHG emissions from the industrial sector.<br/>In order for the energy transition to be successful security of supply affordability and environmental compatibility need to be combined with innovative and smart climate action. This means that the fossil fuels we are currently using need to be replaced by alternative options. This applies in particular to gaseous and liquid energy sources which will continue to be an integral part of Germany’s energy supply. Against this backdrop hydrogen will play a key role in enhancing and completing the energy transition.

Due to the nonideality of a high pressure hydrogen release the possibility of a two-phase flow and its effect on the dynamics of the discharge process was experimentally investigated. A small-scale facility was designed and constructed to simulate the transient blow-down of a cryogenic fluid through a small break. Gaseous and liquid nitrogen were planned to were used as a surrogate for GH2 and LH2. The results will complement the quasi-stationary safety regulation tests and will provide time-dependent data for verification of the theoretical models. Different orifice sizes (0.5 1 2 4 mm) and initial N2 pressures (30 – 200 bar) were used in the tests. The measured time-dependent data for vessel discharge pressure thrust discharge mass flow rate and gas temperatures were compared against a theoretical model for high pressure nitrogen release. This verification for nitrogen also assures the equation of state for hydrogen which is based on the same methodology.

An increase in use of hydrogen for energy storage and clean energy supply in a future energy and mobility market will strengthen the focus on safety and the safe handling of hydrogen facilities. The ability to simulate the whole chain of physical phenomena that may occur during an accident is mandatory for future safety studies on an industrial or urban scale. Together with the RWTH Aachen University Forschungszentrum Jülich (JÜLICH) develops numerical methods to predict safety incidents connected with the release of either LH2 or GH2 using the commercial CFD code ANSYS CFX. The full sequence from the release distribution or accumulation of accidentally released hydrogen till the mitigation of accident consequences by safety devices is considered. For specific phenomena like spreading and vaporization of LH2 pools or the operational behavior of passive auto-catalytic recombiners (PAR) in-house sub-models are developed and implemented. The paper describes the current development status gives examples of the validation and concludes with future work to provide the full range of hydrogen release and recombination simulation.

Hydrogen Infrastructures are currently being built up to support the initial commercialization of the fuel cell vehicle by multiple automakers. Three primary markets are presently coordinating a large build up of hydrogen stations: Japan; USA; and Europe to support this. Hydrogen Fuelling Station General Safety and Performance Considerations are important to establish before a wide scale infrastructure is established.

This document introduces the ISO Technical Report 19880-1 and summarizes main elements of the proposed standard. Note: this ICHS paper is based on the draft TR 19880 and is subject to change when the document is published in 2015. International Standards Organisation (ISO) Technical Committee (TC) 197 Working Group (WG) 24 has been tasked with the preparation of the ISO standard 19880-1 to define the minimum requirements considered applicable worldwide for the hydrogen and electrical safety of hydrogen stations. This report includes safety considerations for hydrogen station equipment and components control systems and operation. The following systems are covered specifically in the document as shown in Figure 1:

• H2 production / supply delivery system
• Compression
• Gaseous hydrogen buffer storage;
• Pre-cooling device;
• Gaseous hydrogen dispensers.
• Hydrogen Fuelling Vehicle Interface

The draft TR 19880-1 (and current plan for the standard) also gives guidance for the fueling validation with safety considerations relevant to the interaction between the hydrogen station and hydrogen road vehicles (during fuelling).. Through a cross-industry risk assessment carried out between OEMs Hydrogen Suppliers and existing vehicle fuelling station providers & operators (e.g. oil and industrial gas companies) the hydrogen fueling protocol SAE J2601 and associated dispenser hardware was evaluated."

The “SUpport to SAfety aNAlysis of Hydrogen and Fuel Cell Technologies (SUSANA)” project aims to support stakeholders using Computational Fluid Dynamics (CFD) for safety engineering design and assessment of FCH systems and infrastructure through the development of a model evaluation protocol. The protocol covers all aspects of safety assessment modelling using CFD from release through dispersion to combustion (self-ignition fires deflagrations detonations and Deflagration to Detonation Transition - DDT) and not only aims to enable users to evaluate models but to inform them of the state of the art and best practices in numerical modelling. The paper gives an overview of the SUSANA project including the main stages of the model evaluation protocol and some results from the on-going benchmarking activities.

The European Strategy Forum on Research Infrastructures (ESFRI) recognizes in its roadmap for Research Infrastructures that ?in the near future hydrogen as an energy carrier derived from various other fuels and fuel cells as energy transformers are expected to come into a major role for mobility but also for different other mobile and stationary applications? |1|. This modern hydrogen driven society lags far behind the reality. Because of that it is conform to question the current situation concerning the belief that already most is comprehensively investigated and developed concerning hydrogen technology is correct and already done. From that it appears the hydrogen technology is market ready only partial and not prepared in a sufficient way to get finally included and adopted in modern hydrogen driven society and especially the acceptance of the society is a critical. Beside this critical view through society several scientific and technical bottlenecks still discoverable. Nevertheless it is possible to foster furthermore science and development on hydrogen technology. The ?Integrating European Infrastructure? was created to support science and development of hydrogen and fuel cell technologies towards European strategy for sustainable competitive and secure energy also while identifying scientific and technical bottlenecks to support solutions based on. Its acronym is H2FC European Infrastructure and was formed to integrate the European R&D community around rare and/or unique infrastructural elements that will facilitate and significantly enhance the research and development of hydrogen and fuel cell technology.