Hydrogen Storage - Recent Improvements and Industrial Prospectives

This paper gives a historical and technical overview of hydrogen storage vessels and details the specific issues and constraints of hydrogen energy uses. Hydrogen, as an industrial gas, is stored either as a compressed or as a refrigerated liquefied gas. Since the beginning of the last century, hydrogen is stored in seamless steel cylinders. At the end of the 60s, tubes also made of seamless steels were used; specific attention was paid to hydrogen embrittlement in the 70s. Aluminum cylinders were also used for hydrogen storage since the end of the 60s, but their cost was higher compared to steel cylinders and smaller water capacity. To further increase the service pressure of hydrogen tanks or to slightly decrease the weight, metallic cylinders can be hoop-wrapped. Then, with specific developments for space or military applications, fully-wrapped tanks started to be developed in the 80s. Because of their low weight, they started to be used in for portable applications, for vehicles (on-board storages of natural gas), for leisure applications (paint-ball) etc… These fully-wrapped composite tanks, named types III and IV are now developed for hydrogen energy storage; the requested pressure is very high (from 700 to 1 000 bar) leads to specific issues which are discussed. Each technology is described in term of materials, manufacturing technologies and approval tests. The specific issues due to very high pressure are depicted. Hydrogen can also be stored in liquid form (refrigerated liquefied gases). The first cryogenic vessels were used in the 60s. In the following, the main characteristics of this type of storage will be indicated.