As the hydrogen economy expands, innovative solutions are needed to overcome the challenges of storing and transporting hydrogen efficiently.
We have explained how, while being the most established methods today for hydrogen transportation, physical-based technologies (compression and liquefaction) present limitations that have an impact in terms of safety, scalability, efficiency, and ultimately costs.
Material-based storage technologies — such as liquid organic hydrogen carriers (LOHC), ammonia, metal hydrides, and reticular materials — are emerging as promising alternatives to traditional compressed and liquid hydrogen storage.
Below we summarize and compare their advantages and limitations in the context of hydrogen transportation. Download our full white paper for a more detailed look into these technologies!
Liquid Organic Hydrogen Carriers (LOHC)
Liquid organic hydrogen carriers (LOHC) are organic compounds capable of chemically bonding with hydrogen in a process called hydrogenation. This reversible reaction allows hydrogen to be stored and transported as a standard liquid at room temperature and pressure.
Advantages of LOHC include safety, with non-hazardous handling conditions compared to high-pressure or cryogenic systems, and a high storage density of 6-7%. On the other hand, releasing hydrogen through dehydrogenation is energy intensive (needs heating to temperatures up to 370°C), leading to high energy costs, and requires specialized hydrogenation and dehydrogenation plants, adding significant infrastructure costs.
Overall, LOHC can offer a compelling alternative to traditional transportation methods, particularly when looking at safety – but remains an expensive technology, especially on large-scale use.
Ammonia
Ammonia is another versatile hydrogen carrier, capable of storing hydrogen in a stable liquid form. Produced via the Haber-Bosch process, ammonia can be transported using existing infrastructure and then “cracked” back into hydrogen at the destination.
Ammonia production and transport are well-established, making it a mature technology with a high hydrogen-to-weight ratio. However, cracking ammonia back into hydrogen leads to energy losses of 15-35%. Toxicity is also a concern, ammonia being a hazardous chemical that requires careful handling and monitoring to prevent leaks.
Overall, ammonia is a promising hydrogen carrier for large-scale applications, but its energy inefficiency and toxicity remain barriers to widespread adoption.
Read Our White Paper to Deep Dive Into Hydrogen Transportation Technologies
[Free Download]
Metal Hydrides
Metal hydrides store hydrogen by chemically bonding it with metallic alloys, offering a solid-state storage solution with high volumetric density.
Metal Hydrides generally show high storage densities, exceeding those of liquid hydrogen at volumetric level. They can operate at moderate temperature and pressure compared to other methods, which constitutes another advantage. However, they present several challenges including:
- Weight: Hydrides are extremely heavy, with only 0.3–1% of their weight consisting of hydrogen.
- Energy Requirements: Releasing hydrogen requires heating to temperatures of up to 300°C, incurring significant energy costs.
- Slow Kinetics: Hydrogen release can be delayed due to a generally slow kinetics.
Overall, metal hydrides hold potential for niche applications, but their weight and energy demands limit scalability.
Reticular Materials: A Novel Approach to Solid-State Hydrogen Storage
Reticular materials, such as metal-organic frameworks (MOFs), represent the cutting edge of hydrogen storage and transportation technologies.
These materials are characterized by microscopic pores within their structure, where hydrogen gas molecules enter and attach to the surface in a process called adsorption. Large amounts of hydrogen can be adsorbed in small volumes of reticular materials due to their exceptionally large surface areas: 1 gram of reticular material can contain an equivalent surface area of up to an entire soccer field!
These highly porous materials can store hydrogen in solid form, at low pressure and near-ambient temperature, presenting unique advantages:
- Customizable Properties: reticular materials can be tailored for optimal storage capacities and release rates.
- Safety: operating at low pressure and ambient temperature, this storage technology is safe to handle and reduces safety concerns associated to high-pressure or cryogenic liquid technologies.
- Energy and Cost Efficiency: by eliminating the need for compression/liquefaction and the related costly equipment and operational costs, reticular material-based storage significantly drives down the cost of delivered hydrogen.
In summary, reticular materials like MOFs have the potential to offer a lightweight, scalable and efficient solution for hydrogen storage and transportation, substantially reducing the cost of delivered hydrogen compared to compression or liquefaction.
Material-Based Storage: The Future of Hydrogen Transportation
Material-based storage technologies present exciting opportunities to improve the efficiency, safety, and practicality of hydrogen transportation. While challenges such as energy intensity and infrastructure costs remain, ongoing research and development are driving these technologies closer to widespread adoption.
To explore the full potential of material-based hydrogen storage technologies, download our white paper today!
