Due to the challenges associated with the electrification of heavy-duty transport (HDV) using batteries, hydrogen has emerged as the leading alternative solution, with two technologies gaining momentum: compressed gaseous hydrogen (CGH2) at 700 bar and liquid hydrogen (LH2). Each technology has its own advantages and challenges in terms of storage, range, energy efficiency, and costs.
Hydrogen Storage Technologies
Compressed Gaseous Hydrogen (CGH2) at 700 Bar
Compressed gaseous hydrogen (CGH2) at 700 bar is one of the most widely used solutions due to the availability of infrastructure and technological advances in high-pressure storage tanks. These tanks allow hydrogen to be stored at high energy densities without the need for extreme cooling. However, this technology requires high-pressure compressors, which can increase the operating costs of refueling stations.
Liquid Hydrogen (LH2)
On the other hand, liquid hydrogen (LH2) offers higher volumetric energy density, allowing more hydrogen to be stored in less space, though handling it requires cryogenic temperatures (-253°C), adding complexity to the infrastructure.
Manufacturers and Vehicle Examples
- Nikola, Toyota, Volvo, and Hyundai: Leaders in the development of CGH2 trucks at 700 bar. A concrete example is the Nikola Tre, which uses 70 kg compressed hydrogen tanks at 700 bar, offering a range of up to 800 km.
- Daimler Truck: At the forefront of developing trucks that use liquid hydrogen (LH2). The Mercedes-Benz GenH2 Truck is designed for long-haul applications, with a capacity of 88 kg of liquid hydrogen (44 kg in each tank), providing a range of over 1000 km.
Differences Between CGH2 and LH2 Tanks
CGH2 Tanks
Advantages:
- Compressed hydrogen tanks at 700 bar are safer to handle at ambient temperatures and do not require advanced cryogenic systems.
- They are less susceptible to long-term evaporation losses and offer greater operational flexibility in everyday applications.
Disadvantages:
- They are bulkier and heavier, which can reduce the vehicle’s payload capacity.
- Manufacturing costs are higher due to the need for advanced materials, such as carbon fiber, to withstand high pressures.
LH2 Tanks
Advantages:
- Liquid hydrogen tanks have higher energy density, allowing more hydrogen to be stored in a smaller space.
- They are ideal for long-haul applications and enable faster refueling.
Disadvantages:
- They require advanced cryogenic systems to keep hydrogen at -253°C, which increases system complexity.
- They are susceptible to hydrogen losses through evaporation if not used quickly (boil-off).
Conclusions
Both compressed hydrogen and liquid hydrogen offer advantages and disadvantages that should be considered when selecting the best solution for heavy-duty vehicles (HDV). CGH2 offers more stable infrastructure and fewer technical storage requirements. On the other hand, LH2 allows for greater range and better space utilization, though it involves greater technical complexity due to the low temperatures required for storage.
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