Challenge
The ideal hydrogen storage:
light, affordable, safe
An optimal hydrogen storage has little efficiency loss, requires minimal safety precautions, and can store large amounts of H2 in a small space. For mobile storage solutions, transport should be simple and inexpensive. The weight of the storage unit plays a particularly important role. Although pressure and liquid storage of hydrogen are already commercially established solutions today, the existing physical and chemical storage technologies are far from ideal for hydrogen storage.
Hydrogen has a very high permeability and can diffuse through porous materials or even metals. Therefore, storage requires special materials to minimize diffusion losses.
Goal: minimal energy losses during conversion and storage
Efficient hydrogen storage seeks to minimize the loss of hydrogen and energy during the storage process as much as possible. To keep the energy required for compression to a minimum, the pressure with which the hydrogen emerges from electrolysis (30–60 bar) is utilized. When hydrogen undergoes a chemical transformation for storage purposes, the two-step conversion process (hydrogen => chemical storage medium => hydrogen) should consume as little energy as possible.
Advantages and disadvantages of different
hydrogen storage technologies
Physical pressure storage
Advantages
- Inexpensive
- Already in commercial use
- Compensates for the low volumetric energy density of H2
Disadvantages
- Compression consumes energy (5–12% of the H2 energy content)
- The higher the pressure, the larger the storage vessel/the wall thickness
- High transport costs due to weight
Physical storage of liquid hydrogen
Advantages
- Significantly higher volumetric energy content compared to physical storage
- Easier transport
Disadvantages
- High energy loss in the storage process (30–40%)
- Highly insulating special steel tanks necessary
- Cooling units required
Today’s physical H2 storage has central disadvantages: high efficiency losses due to compression or cooling and high requirements for material stability and safety precautions.
Chemical H2 storage
Advantages
- Easy handling
- Lower safety requirements
- Good transportability
Disadvantages
- High energy efficiency losses in the storage process
In chemical storage, hydrogen is combined with other elements. These can be hydrides (metal alloys), nitrogen compounds such as ammonia, aminoborane, or hydrazine, or hydrogen carriers that absorb hydrogen through a chemical reaction with the help of catalysts and release it through another chemical reaction.
Typical application scenarios
for hydrogen storage
Markets with the greatest potential for decarbonization through green hydrogen
Industry
- Reactant: Steel from direct reduction
- Material use: Ammonia, chemicals
Energy sector
- As long-term storage for renewable energies
Transport
- Long-distance truck traffic
- Long-distance air traffic
- Long-distance maritime traffic
Housing
- District heating for residential and office buildings
Which type of hydrogen storage
for which application?
Stationary Applications
Pressure gas storage with PED approval, which are placed and filled directly at the place of consumption.
Transport
Refilling of the TPED-approved fuel storage systems for ships at the HydroExceed hydrogen hub in Rostock-Laage, as well as their transportation to the customer.
Mobile Applications
TPED-approved hydrogen storage systems for operating vehicles, particularly in the maritime sector. The filling and emptying processes occur directly at the site of operation.