What Is the Difference Between Compressed and Liquid Hydrogen?
One of the key measures we can take to achieve a carbon-free economy is implementing effective storage and transport of hydrogen. The two most effective methods are compressing or liquefying the hydrogen. With the advancement of technology over the next few years, it may also be possible to create a hybrid approach for storing and transporting the gas.
What Is Compressed Hydrogen?
This is condensed hydrogen stored in a gaseous form. Hydrogen gas is compressed at increased air pressure and placed into gas cylinders or tubes to be transported. The process allows us to keep a higher density of hydrogen gas in a smaller space.
Advantages:
- High-density hydrogen storage.
- Existing gas cylinder and tubes for storing and transporting.
- Provides enough gas to power a hydrogen fuel cell vehicle for 500-600 kilometres before a refill is required.
- Scientists are developing lighter, composite cylinders and tubes that will increase the capacity to transport and store in larger volumes.
What Is Liquid Hydrogen?
This is hydrogen that has been liquefied and stored in a fluid form. This type of hydrogen has a much higher density than compressed hydrogen. The process of liquefaction involves cooling hydrogen gas to below 253°C and then storing it in an insulated tank. The most common use of liquid hydrogen is as rocket fuel for space travel.
Advantages:
- Has a 4.5 times higher density than compressed hydrogen.
- The storage solutions for liquid hydrogen are lighter.
- Liquid hydrogen allows for easy transport in large quantities to fuel stations.
- Liquid hydrogen can be used to power mass transit systems like buses.
