Because hydrogen gas has such a low density, and because the energy requirements for hydrogen liquefaction are high, efficient hydrogen storage generally is considered to be among the most challenging issues facing the hydrogen economy. For current chemical applications, storage issues are not so critical, because the large producers of hydrogen both generate and consume the gas simultaneously on site, thereby reducing storage and distribution requirements significantly.

Stationary Storage Systems

Very large quantities of hydrogen can be stored as a compressed gas in geological formations such as salt caverns or deep saline aquifers. There are two existing underground hydrogen storage sites in the United States. In addition, the co-storage of hydrogen with natural gas has been proposed. There are 417 locations in the United States where natural gas is currently stored in rock caverns, salt domes, aquifers, abandoned mines, and oil/gas fields, with a total storage capacity exceeding 3,600,000 million cubic feet. Hydrogen stored in salt caverns has the best injection and withdrawal properties.

Source: U.S. Energy Information Administration