The amount of gas that can be stored to cover peak demand. The main types of storage (apart from pipeline storage) are:

1) Liquefied natural gas (LNG) – gas cooled until in liquid form at -162° Celsius and stored in insulated metal tanks.

2) Salt cavities (caverns) – many cavities have been created underground by dissolving layers of salt.

3) Aquifers (porous rocks).

4) Depleted gas fields now converted into storage facilities.