Natural gas is continuously extracted throughout the year even though its consumption varies depending on the time of day and the seasons. On a winter day, gas consumption can be 8 times higher than on a normal summer day. Fluctuations observed throughout the day can also be significant. 

Storage allows this energy to be held for a later use: gas surplus received during the summer is stored for use during the cold winter period.

For seasonal storage, underground geological structures are often used. Watertight cavities, once drained of the water or salt they contained, are used to store injected natural gas. Another possibility is to create an artificial rock cavity.  

The largest aquifer reservoir, located in Chemery in France, can hold 7 billion metre cubes of natural gas, which equates to over twice the annual gas consumption for Switzerland. Gaznat has storage capacity in saline cavities in the area of Bourg-en-Bresse in France. 

To even out daily or weekly consumptions, storage in buried pipelines are generally used, such as in Volketswil, in the Zurich canton.