Strategic fuel storage and the problem of empty capacity

What do countries other than the United States use to store strategic fuel reserves?

Salt caverns, suitable mines, bunkers and concrete-lined underground spaces are cited, with the warning that storage capacity is useful only when stocked.

Britain and Sweden are among the examples mentioned for underground fuel storage. Adapted mines and excavated spaces offer alternatives to salt caverns. Empty reserves depend on a crisis providing enough warning to fill them, an assumption criticised here. Energy resilience therefore depends on funding stocks in advance as well as providing storage capacity. No site inventory or measured reserve level is established.