Hydrogen projects are expanding across transport, energy and industrial processing, with global demand projected to rise through to 2030 according to The International Energy Agency (IEA). These systems place heavy demands on small rotating parts, and any change in friction, temperature or material behaviour can lead to wear. Here, Chris Johnson, managing director of bearing specialist SMB Bearings, explores why components such as bearings have a direct impact on the safety and stability of hydrogen systems.
Worldwide hydrogen demand increased to almost 100 million tonnes in 2024, up two per cent from 2023 and in line with overall energy demand growth, according to the full report from the IEA. As more projects come online, the equipment supporting these systems is working harder and for longer periods, which places added pressure on smaller mechanical parts.
Miniature bearings sit at the centre of many of these applications, supporting components that control pressure, manage flow and maintain temperature within critical assemblies. If these bearings begin to wear or seize, the impact can surface long before a major component raises an alarm.
For example, a blower in a fuel cell system can lose airflow and cause overheating. Similarly, other rotating components can experience issues that escalate quickly if not detected early. A bearing in a pump can create friction that leads to temperature spikes. In more extreme environments, these risks become even greater. In a cryogenic unit, stiffness caused by low temperatures can place strain on shafts and seals, raising the possibility of leaks.
Hydrogen embrittlement adds a layer of risk
One of the most significant factors is how hydrogen interacts with metals. Research from the University of Cambridge notes that hydrogen can enter the surface of bearing steels and alter their microstructure, making them more prone to cracking under load. As this process develops, small cracks can form and grow during normal operation. This behaviour, known as hydrogen embrittlement, raises the risk of sudden failure in bearings used in compressors, expanders or pumps.
Combined with the very low temperatures required for hydrogen liquefaction or the high speeds found in rotating equipment, embrittlement adds further stress to parts that are already operating under tight tolerances. A 2023 report from Process Safety and Environmental Protection highlights that, while hydrogen offers a carbon-free alternative, its hazards — like embrittlement — demand a heightened focus on safety.
An example can be seen in high-speed expanders used in a liquefaction plant. These machines rely on small bearings that must rotate at high speeds while resisting sudden temperature changes.
If the bearing begins to crack due to embrittlement or loses lubrication at low temperatures, the expander can develop imbalance. As vibration grows, the machine may shut down to prevent further damage. What appears to be a large mechanical issue may later be traced to a bearing only a few millimetres in diameter.
Fuel cell systems provide another illustration. These systems depend on steady airflow to maintain temperature in the stack. A small blower uses a miniature bearing set to keep the rotor moving with minimal friction. If the bearing lubricant thickens in cold conditions or begins to break down under load, the blower may slow down. This can lead to rising temperatures in the stack, reduced performance or early shutdown. Again, the issue originates in a small component rather than the larger assembly.
Cryogenic pumps take this further. Hydrogen cools to below minus 150 degrees Celsius when converted to a liquid. At these temperatures, metals contract and lubricants behave differently. A miniature bearing that performs well at ambient conditions can struggle under these extreme shifts. If friction increases, wear can accelerate and the pump may lose stability. In systems where even minor leaks can create risks, the correct bearing choice becomes a central part of safe operation.
Careful bearing selection
Miniature bearings appear throughout hydrogen technology. In high-speed compressors, they support auxiliary drives and small control stages. In fuel cell systems, they keep blowers and pumps running smoothly. Aerospace propulsion research uses miniature bearings in sensors, actuation units and pumps, where low weight and precision are key. Hydrogen liquefaction plants rely on them in expanders, valves and cryogenic pumps, all of which operate under cooling regimes that test the limits of bearing materials.
Selecting suitable bearings for these environments require careful attention to materials, seals and lubrication. Because these applications expose components to moisture, high speeds and extreme temperatures, material choice becomes particularly important.
Stainless steel bearings, often made from 440C or 316 grades, offer resistance to moisture and corrosion. When more durability or lower wear is needed, hybrid bearings, which combine ceramic balls with steel rings, reduce wear and are less affected by embrittlement. Hybrid bearings with high nitrogen stainless steel rings offer greater resistance to embrittlement. For the most challenging conditions, especially in cryogenic systems, full ceramic bearings provide corrosion resistance, temperature stability and low friction, making them a strong choice.
Seal design also plays an important role. Contact seals offer strong protection against contamination, though they may introduce slight drag. Non-contact seals balance protection with low friction. In hydrogen environments, where leakage paths must be kept to a minimum, the correct seal can help maintain lubrication and protect the bearing from debris.
Bearing lubrication must also be considered carefully. At low temperatures, some oils and greases can thicken, creating drag and raising friction. Solid lubrication or dry film coatings can reduce wear where access for maintenance is limited. Choosing a lubricant that remains stable under both ambient and cryogenic conditions helps maintain consistent bearing performance.
System-wide consequences
Hydrogen systems are defined by large compressors, storage vessels and pipelines, but the early signs of instability often begin in smaller places. Bearings influence how valves move, how pumps circulate hydrogen and how blowers maintain airflow in fuel cell stacks. A failure in one of these areas may cause shutdowns, rising temperatures or pressure fluctuations that interrupt normal operation.
SMB Bearings supplies stainless steel, ceramic and hybrid miniature bearings designed for challenging environments. Their products support rotating assemblies within compressors, pumps, expanders and cryogenic systems. By selecting the right bearing materials, lubrication and sealing, engineers can improve reliability and reduce the likelihood of unplanned downtime in hydrogen applications.
For more information on miniature bearings for hydrogen-related applications, visit the website.www: http://www.smbbearings.com/
