A Review on Hydrogen Compression Methods for Hydrogen Refuelling Stations

Hydrogen is considered to be the fuel of the future, since it has the potential to store excess energy produced by renewable energy sources and then be used either as energy storage for power production by utilizing fuel cells or as a transportation fuel. For these reasons, it can be considered as the missing link between various industrial sectors, leading at the same time to increased renewable energy penetration and the decarbonisation of the sectors in which it is used. Since the transportation sector presents one of the most polluting sectors of human activity, it can be easily understood that utilizing hydrogen as a fuel for vehicles could lead to a significant reduction in carbon emissions. The main issues regarding the large-scale adoption of hydrogen as a fuel are its storage and its efficient compression. The solution of the latter issue, though, can lead to the solution of the former as well, since storing compressed hydrogen in high-pressure vessels presents one of the most commonly used methods of storage and the higher the pressure in which it is stored, the higher its energy content per unit volume. One could assume that by developing cost-efficient and environmentally friendly compression methods, the cost of compression, which currently amounts to almost half of the total cost of a hydrogen refuelling station, would drop substantially, leading to further adoption of hydrogen as a fuel for transportation. This work presents a review on state of the art for hydrogen compressors, be it either mechanical or non-mechanical, covering their operation principles, their applications as well as their benefits and drawbacks. More specifically, the contents of the current chapter area include: reciprocating, diaphragm, metal hydride and electrochemical compressors.