Hydrogen and ammonia safety solutions for the energy transition

Although hydrogen has been in use for a long time in industries such as the chemical industry and fertiliser production, the use of hydrogen is now being explored in a number of relatively new applications such as transport. For example, hydrogen cars and buses are already in use in some countries. Hydrogen powered ferries and ships are at an advanced stage of development in some countries like Norway and Japan. Hydrogen-powered trains and aircraft are being developed at the moment.

The use of hydrogen is also being explored to decarbonise heavy industries. For example, hydrogen is being trialled in the cement and steel production sectors.

Two main technologies exist at the moment: Hydrogen-fuel cell vehicles (HFC), which are essentially electric cars using hydrogen to generate electricity in a fuel cell and Internal Combustion Engines (ICE), which operate in the same way as traditional gasoline and diesel engines. Hydrogen ICE are more efficient at high loads, for example for heavy trucks, while HFC vehicles are more efficient for light duties.

The two most common ways of storing and handling hydrogen is either as a highly pressurised gas or as a cryogenic liquid.

In order to achieve a reasonable volumetric energy density, gaseous hydrogen needs to be pressurised to at least 300 bar and some applications require up to 700 bar.

Liquid hydrogen is a cryogenic (extremely cold) liquid, and it needs to be kept below -253 C° to stay liquid. Given the extremes of temperature or pressure required, storing hydrogen has unique challenges. Other methods for storing hydrogen are being researched at the moment, like metal hydrides and liquid organic hydrogen compounds but these are at a very early stage of development.

Hydrogen has been used safely in industry for many decades. The new challenge is that H2 is now being used in much closer proximity to the public and in environments that are not as tightly regulated.

For example, it would be members of the public who would refuel their vehicles using high pressure hydrogen. Therefore, it is essential that hydrogen-handling systems are designed to be very robust and error tolerant, meaning that the system will shut-down safely if it is used in an inappropriate or unintended way.

Both technology and infrastructure developers, commercial operators and regulators need to develop a thorough and detailed understanding of the hazards in their particular application, how are these hazards being mitigated and what needs to be done to reduce hazards to a tolerable level.

It is also important for operators and emergency responders to understand what could happen if there was an accidental release of hydrogen and how to respond to it. Awareness and training in the specific hazards of hydrogen as well as commitment from all involved parties to design their equipment to the highest standards to ensure safety will be essential for hydrogen safe deployment. In order to better understand some of the specific hazards of hydrogen such as fires and explosions there are several international research projects underway at the moment and Gexcon is participating in a number of them.