In the global push to decarbonize, hydrogen is a key driver of carbon neutrality. Fullcryo, a global producer of liquid hydrogen, reveals which form of hydrogen is better suited for energy storage and transportation, liquid or gaseous hydrogen?
At normal temperature and pressure, hydrogen exists naturally in gaseous form. Like all gases, natural hydrogen has a low density. Even at a high pressure of 700 bar, the volumetric energy density of gaseous hydrogen is only 5.6 MJ/L, meaning that 1 L of gaseous hydrogen produces only 5.6 MJ of energy.
This property means that meaningful storage requires either huge tanks or high pressure compression.
Liquid hydrogen: denser but extreme conditions
To convert hydrogen into liquid form, it must be cooled to ultra-low temperatures of -253°C (-423°F). Liquids are denser than gases, and liquid hydrogen has a higher volumetric energy density of 8 MJ/L.
Liquid hydrogen is about 10 times denser than gaseous hydrogen, which greatly reduces the space required for storage and transportation.
To convert hydrogen to a liquid state, it must be cooled to ultra-low temperatures of – 253°C (-423°F). Because liquids are denser than gases, liquid hydrogen has a higher volumetric energy density of 8 MJ/liter.
Liquid hydrogen is about 10 times denser than gaseous hydrogen in terms of density, which greatly reduces the space required for storage and transportation.
There are various methods for producing gaseous hydrogen, mainly including:
Electrolysis: water is decomposed into oxygen and hydrogen by electricity (if the electricity comes from renewable energy, “green hydrogen” can be produced).
Thermochemical method: hydrogen is released by heat and chemical reactions (for example, from natural gas, biomass).
Biological method: hydrogen is produced by microorganisms through fermentation or photosynthesis.
The collected gaseous hydrogen is compressed to store more gas in tanks or hydrogen energy centers.
Fullcryo uses mature and advanced pressure swing adsorption hydrogen purification technology to produce hydrogen products with a purity of up to 5N and above from raw gas, realizing the comprehensive utilization of resources and reducing pollution.
The production of liquid hydrogen begins with gaseous hydrogen (regardless of its source), which is subsequently converted by a low-temperature liquefaction process. Examples include the use of technologies such as the helium turbine reverse Brayton cycle or the hydrogen Claude cycle.
In the case of Fullcryo’s technology, for example, the core components of the liquefaction plant include a cold box, a compressor, an expansion turbine, and so on. It is worth noting that the liquefaction process consumes a lot of energy, which is a key trade-off.
Approach: High pressure tanks (up to 700 bar) or low pressure reservoirs. Advantages: Relatively low infrastructure for small scale storage.
Advantages: Relatively simple infrastructure and less upfront complexity for small-scale applications.
Disadvantages: High space requirements; high pressure increases safety and maintenance costs.
Requirements: Requires cryogenic tanks to maintain a temperature of – 253°C while relying on vacuum insulation to minimize heat intrusion. Advantages: Significantly reduced size (compared to a vacuum insulator).
Advantage: Significant volume reduction (~800 times less than gaseous hydrogen), ideal for large-scale storage.
Disadvantages: There are “evaporation losses” (hydrogen evaporates at elevated temperatures); requires specialized storage infrastructure.
Gaseous hydrogen is less suitable for long-term storage due to the need to maintain pressure; liquid hydrogen is more suitable for long-term storage (e.g., for energy backup systems) as long as low temperature conditions are maintained.
Modes: high-pressure tube bundles trucks (road), pipelines (for high flow rates).
Advantages: mature pipeline network already exists in some areas; relatively simple transportation over short distances.
Disadvantages: high cost of high-pressure transportation; limited amount of single transportation (the carrying capacity of tube bundle trucks is much lower than that of liquid hydrogen carriers).
Mode: cryogenic tanker trucks (road, rail, ship) designed for storing ultra-low temperature liquids.
Advantages: more energy in a single transport due to high density; more cost-effective for long-distance transportation (e.g., cross-country or transcontinental).
Disadvantages: requires specialized tanker trucks; possible energy loss due to evaporation during transportation.
As Dr. Rainer Küngas, Stargate’s Chief Technology Officer for Hydrogen, explains: “Gaseous hydrogen is so light that, from a purely energy-dense point of view, large-scale storage would either require oversized tanks or high-pressure compression. Converting hydrogen to liquid form, on the other hand, makes it more compact and easier to transport over long distances.”
The main reason for liquefying hydrogen is simple: efficiency. Gaseous hydrogen has a low energy density, making it difficult to store and transport on a large scale. When liquefied, hydrogen dramatically shrinks in volume by a factor of about 800, which is critical for scenarios that require large amounts of hydrogen energy.
This volume advantage makes it attractive for scale-up applications, such as meeting the needs of heavy transportation, grid energy storage, and large-scale industrial manufacturing. It also makes it possible to transport hydrogen energy across regions and even countries, expanding the range of hydrogen energy applications.
During the hydrogen liquefaction process, harmful impurities are cured, and when it is vaporized and used again, the hydrogen purity grade can reach 6-7N, which can effectively improve the power and life of hydrogen fuel cells.
The working pressure of liquid hydrogen storage and transportation is 1-1.3 bar, which has higher safety compared to high pressure gas hydrogen storage and transportation methods.
Energy storage: more suitable for large-scale, long-term energy storage (such as storing excess electricity generated by solar and wind power for grid stability).
Transportation: more suitable for long-distance heavy-duty transportation (cryogenic tankers, ships) and aerospace (such as NASA for rocket fuel).
Industrial: For large-scale industries that require a lot of hydrogen energy (such as ammonia production), building liquid hydrogen plants can improve cost-effectiveness.
With the advancement of technology (such as more efficient liquefaction systems developed by companies such as Fullcryo), the application threshold of liquid hydrogen may be further lowered, helping to build a global hydrogen energy network.
Fullcryo has extensive experience in liquid hydrogen solutions, providing liquefaction plants from small scale (200-2500 kg/day) to large scale (5-100 tons/day). Whether you need gaseous or liquid hydrogen solutions, the right partner can optimize storage and transportation. Contact us to explore customized solutions.
