Underground Gas Storage

By definition, all subsurface and surface facilities required for gas storage are underground gas storage. In most cases, natural or man-made spaces underground are used, located between geologically impermeable layers. Thus, an underground gas reservoir can be, for example, an old mined mine, or a deliberately constructed space where gas is injected for part of the year so that, if necessary, it can be extracted again and released into the pipeline network.
The primary purpose of the reservoirs is to optimize the use of the gas system. Indeed, gas consumption is variable in the year, and if the infrastructure was sized to maximum consumption (in the winter period), the entire network would not be fully utilized for a long part of the year and there would be inefficiencies. The reservoirs are thus primarily designed to compensate for seasonal differences in gas consumption.
In recent years, however, they have often been used as a "safeguard" for energy security, in addition to optimization, in case of disruption of gas supplies to the Czech Republic. Another substantial advantage is the possibility of using gas in the tip cap reservoir, when there is no need to purchase short-term expensive gas on the spot market.