Hydrogen storage: options at a glance

Natural gas storage is closely linked to the future of hydrogen storage, as corresponding storage facilities for natural gas can also be used for hydrogen. Hydrogen is stored under high pressure in specific tanks and under extreme cooling in liquefied gas storage facilities. Underground pressurised gas storage of hydrogen also offers great potential. Background to the natural gas supply: Germany has only limited natural gas reserves and has to import 80% of its requirements. Against the background of a reliable energy supply, gas storage facilities therefore play an important role. Huge, mostly underground facilities can compensate for seasonal fluctuations in demand and supply bottlenecks. Almost a third of Germany's annual consumption of natural gas is available as a reserve in this way. Surface storage facilities are also used to manage consumption peaks at a local level or to cover industrial requirements.

From the design review of pressure vessels, tanks and test modules to the acceptance of hydrogen-powered vehicles and the performance of all recurring tests - with comprehensive services in the areas of testing, inspection and certification, we support you in the following phases of your respective project: concept/planning - production - operation

We are your experienced partner in the comprehensive production monitoring and testing of pressure vessels as well as in the development of prototypes for mobile and stationary applications. With competent specialists and modern analysis and measurement methods, we provide reliable findings on the resilience of the materials used, ensure conformity with national and international regulations and support you in benefiting from subsidies.With our expertise, know-how and many years of experience, we are an independent partner for safety and hazard prevention by being able to test, inspect and certify various aspects of hydrogen technology.

Small to medium-volume gas tanks in metal construction are used for above-ground pressurised gas storage. Tubular storage tanks embedded in the ground enable high nominal pressures and the storage of larger quantities of gas. Specific high-pressure tanks are used to store hydrogen. Due to its physical properties, hydrogen is compressed under high pressure for storage, in some applications up to 1000 bar. Liquid hydrogen (LH2 = liquid hydrogen) requires a storage temperature of -253 °C, which requires larger containers with high-performance insulation.

Gaseous hydrogen compressed under high pressure (CGH2= Compressed Hydrogen) is stored and transported in cylindrical steel containers , while lighter, carbon fibre-coated containers made of aluminium or plastic are used as hydrogen storage tanks in fuel cell vehicles. In addition, hydrogen can be stored for small applications in metal hydride storage tanks or, on a large scale, in liquid carrier media (LOHC = Liquid Organic Hydrogen Carrier).

In the area of geological possibilities for compressed gas storage, both the cavities of salt domes (caverns) and less accessible "pore spaces" of former gas and oil reservoirs, as well as water-bearing aquifers, can be used for hydrogen storage. It should be noted that the storage volume of an underground storage facility can only be partially utilised.

It should be noted that the storage volume of an underground storage facility can only be partially utilised effectively. A certain minimum pressure must be maintained in the reservoir in order to preserve the mechanical properties of the reservoir rock and to optimise operation during the injection and withdrawal of the gas. The portion of the gas that is required to maintain this "minimum operating pressure" and therefore cannot be effectively utilised is called "cushion gas". The proportion of gas that can be injected and withdrawn at any time is called "working gas". The relative proportion of cushion gas to working gas can vary greatly depending on the type of storage tank.

With a view to mobile and portable applications, the storage of gaseous hydrogen in metal hydride storage systems comes into consideration. To date, compact solid-state storage systems still have a relatively low storage capacity for hydrogen compared to their own weight. However, their low storage pressure offers advantages for storing hydrogen safely. In this respect, these hydrogen storage systems differ in particular from conventional high-pressure or cryogenic storage technologies. As part of a fully established hydrogen infrastructure, advanced metal hydride storage systems could be increasingly used in the future - for example as fuel cell system components in vehicles or in small fuel cell-powered devices such as portable computers.