Natural gas storages provide a reliable supply of natural gas. Within the EU Germany owns the largest storage volume at present. Nationwide plants with a total capacity of about 25 billion cubic metres are in operation, thus enabling a stable and flexible supply of natural gas required in the market.

To make optimal use of the production and transport systems natural gas is being imported continuously in contractually fixed volumes, irrespective of the actual demand. This differs substantially according to the season: Sales on cold winter days can be six times as high as on summer days.

In times of low consumption natural gas is injected in the storage. If demand rises, the stored natural gas is available for withdrawal.

In that way natural gas storages balance intense fluctuations in consumption and secure a year-round stable supply of energy. They form not only an essential link between natural gas production and consumer. Natural gas storages also play an important role in the liberalised gas market concerning the optimisation of the gas trade. Since 2009 the pairing natural gas trade/ sales, gas storage and grids, which are regulated by the state, are being operated separately within the EU Single Market. None of the market participants is able to safeguard the supply on its own. It is only the optimal cooperation of all parties involved that guarantees a stable supply of natural gas - for private households as well as for the industry.

European gas traders use natural gas storages on the one hand to balance fluctuations in demand and to warrant supply of energy also in case of delivery delays. On the other hand the storages enable traders to optimise their gas supplies as well as their trading portfolios.

For grid operators the natural gas storages represent an important source for external balancing energy (Regelenergie). This energy is required in case of an imbalance between injection and withdrawal in the market area which requires an adjustment of the balancing group.

Natural gas is stored in underground pore or cavern storages. They are located at 500 to 2,500 metres depth down below ground.

Currently RWE Gas Storage West operates and markets exclusively cavern storages. These artificial cavities in deep saline formations can have a height of up to 100 metres and a diameter of 80 metres.

In each cavern storage there is a certain amount of gas deposit - the cushion gas. It safeguards the stability of the cavern. On top of that, the physical properties of the salt layer make for a natural sealing.