Safety, durability and reliability for the hydrogen economy

Hydrogen is a promising energy source, and safety is the top priority when using it. Comprehensive procedures to qualify materials and components for hydrogen applications are therefore essential. These procedures must cover applications ranging from electrolysis and storage through to the mobility, heat/energy and industrial sectors. The question of service life is closely linked to that of safety. The Fraunhofer institutes contribute their expertise to a wide range of industrial and publicly funded projects addressing both these aspects, and also provide the corresponding testing facilities.

The safe and sure path to more hydrogen!

The transformation to a climate-neutral society requires broad acceptance of the hydrogen economy. In particular, this means a high level of trust in the operational safety of hydrogen systems. Safety and accident risks must be excluded or minimized as far as possible. The operators of plants for the production, storage, distribution and use of hydrogen must ensure a long service life and high reliability of the plants. This can be achieved through adapted service life models, the selection of qualified materials and the control and systematic monitoring of relevant status and process data. The good reputation of innovative hydrogen technology »made in Germany« is therefore not based solely on the technology itself: safety, durability and reliability are also required at the highest level in order to be considered an international benchmark.

This guiding principle applies to all technical systems that must provide added value for the customer and end-user while at the same time offering a long service life and high reliability. Further important factors are lightweight construction and high material efficiency without cost increases for the users. Technologies developed specifically for the hydrogen economy as part of the energy transition also need to be analyzed in terms of their availability, safety, reliability and service life. Besides electrolysis systems and fuel cells for mobile applications, this includes the analysis of systems and infrastructure components, for example when hydrogen is distributed via the former natural gas network.

The planned use of the energy carrier in the processing industry – which, like the steel industry, has had no previous contact with this reducing agent – is also relevant. Developers, manufacturers and users are faced with numerous questions regarding the appropriate service life model, the right choice of materials, system monitoring and safety assessment. However, there is also a need for methods to assess system reliability and resilience. If the weak points are not identified, the safety, functionality, reliability and service life of components and systems will continually be compromised by hydrogen-specific material damage resulting from mechanical, thermal, chemical and electromagnetic loads during operation. This can be countered by adapted service life models, the selection of materials with high H2 corrosion resistance and systematic and planned monitoring.
 

Hydrogen all the way – but safely, reliably and for the long-term!

Nine Fraunhofer institutes from the Fraunhofer Hydrogen Network, with expertise in system analysis, safety, service life and reliability, are working intensively together on precisely these issues. They have pooled their expertise in a working group so that they can reach out to specific customers and address the challenges they face. In the context of the hydrogen economy, the members work on issues relating to hydrogen-specific service life models, material damage and damage detection, the monitoring of hydrogen-carrying components, the recording of status and process data, the modeling and simulation of safety and reliability scenarios and their experimental evaluation. The working group deliberately focuses on the safety, design and optimization of systems, processes and components such as H2 electrolyzers, infrastructure components, fuel cells and storage systems.

This work is supplemented by research and development activities based in the hydrogen test fields, which arise from the results of the investigations. Methods are being developed that enable effective, holistic system evaluation and monitoring, examining system behavior down to the material level using digital sensors and sensor materials. These methods ensure a continued high availability of systems, processes and mobility applications through the early detection and assessment of damage processes relevant to safety and service life, which in turn enables timely maintenance work. It is particularly important to ensure that the methods and concepts developed by the research institutes are both safe and relevant for the application.

The working group also participates in scientific and standardization committees to develop standards, guidelines and implementation recommendations relating to hydrogen.

Safety through visibility – making hydrogen visible

Hydrogen is already an important source of energy, and its significance will continue to grow in the coming years in both the industrial and the private sectors. Hydrogen cannot be seen, smelled or directly perceived with other human senses. Measures must therefore be taken to make hydrogen perceptible – quickly, cost-effectively, safely and comprehensibly. This is the only way ensure the safe use of hydrogen in households and industry. Fraunhofer ISC, together with a university partner1 has developed a concept for the simple detection of hydrogen using a novel, particle- based powder indicator. Like a traffic light system, this indicator can show the presence of hydrogen via a twostage color change. The key feature of this flexible powder indicator is the structure of the individual particles.

These are so-called supraparticles, which are produced by spray drying and consist of thousands of smaller nanoparticles. Various components (carrier particles, catalyst particles, dye) are used in these hydrogen indicator supraparticles, all of which have a specific function in the detection of hydrogen gas.

The supraparticular structure allows a microenvironment to be created in the smallest of spaces, in which a sensitive dye can change its molecular structure and thus its color. If the superparticle comes into contact with hydrogen, the gas can penetrate its pore system and dissociate on the reactive surfaces of its catalyst particles. The activated hydrogen atoms then react with the dye molecules and first reduce them irreversibly, resulting in an initial color change from violet to pink. On further exposure to hydrogen, the dye molecule is further reduced and a second color change from pink to colorless occurs. As soon as the hydrogen is removed, the dye molecule releases the bound hydrogen and returns to the pink-colored state.

This creates a traffic light system that indicates the presence of hydrogen in the ambient air by means of a simple color change. The chief advantage of this newly developed supraparticulate powder is its wide range of potential applications and its simple and cost-effective production on a large scale. Defective sealing in pipes can be detected when the powder is integrated into gloves or leak detection sprays. Incorporated into the coating for example of hydrogen filling stations, cars or heating systems, the color change can quickly and easily draw attention to a hazard. No electronic devices or specialist personnel are required to detect the results, as the color change can be seen by anyone with the naked eye.