Natural gas storage

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Natural gas storage facility in Kiel (1962)

As natural gas storage large, mostly underground storage facilities are referred to which seasonal fluctuations in demand and supply shortages of natural gas can be compensated. The storage tanks are usually filled in the summer months and partially emptied during the heating season . These storage facilities became very important for Central and Western Europe in 2009 when there were delivery restrictions between Russia and the Ukraine, which is why their capacities have been massively expanded in recent years.

Daily consumption peaks, on the other hand, are compensated for by smaller surface metal storage facilities. They are available as low-pressure accumulators (gasometer) and high-pressure accumulators ( ball and tube accumulators ).

There are currently 51 underground natural gas storage facilities in Germany for a total of 24.6 billion cubic meters, which corresponds to around 28 percent of German annual consumption. Storage facilities for hydrogen gas are also planned for the future . Austria has capacities of over 7.5 billion cubic meters (from Rohöl-Aufsuchungs AG (RAG) with 5.7 billion cubic meters and OMV with 2.4 billion cubic meters.) In the gas crisis of 2008, these storage facilities also supplies neighboring countries and thus ensures the supply. The largest storage facility in Austria with a capacity of 2.6 billion cubic meters is located in the municipality of Haidach near Salzburg . The Russian Gazprom Export , the German gas trader Wingas and the Austrian Rohöl-Aufsuchungs AG each hold a third of this storage facility .

The largest natural gas storage facility in Western Europe has been the Rehden storage facility in Lower Saxony since 1993 with a working gas capacity of 4 billion cubic meters. The annual consumption of around two million single-family homes is stored in three depleted deposits 2 km deep in the main dolomite on an area of ​​8 km².

Underground storage

Natural or artificial cavities 1–3 km deep, which are filled with up to 250 bar overpressure, are used as underground or underground storage. They are available in three types:

  1. Former gas or oil deposits : some of the extracted natural gas fields can be refilled if the rock is suitable. The reservoirs in the Upper Austrian Molasse zone and near Matzen in the Vienna Basin are of this type ; Russian imported gas is stored in the latter from the Baumgarten / March distribution station .
  2. Cavern storage facilities are used for short-term fluctuations in demand and are generated in salt domes by extracting brine. The slow flow behavior of rock salt ensures the sealing of these cylindrical, up to 100 m wide cavities . In Westphalia there are 45 cavern storage facilities for a total of 2.5 billion cubic meters of natural gas. Some can also be filled with petroleum , with salt solution used to compensate for volume.
  3. Pore storage facilities use the fissures and pores of subterranean limestone and sandstone layers that are sealed upwards by impermeable rock. They can be cavities from which water is displaced by injected natural gas or where natural gas has already been extracted.

The storage volume of an underground storage facility can only be partially used (working gas). The so-called cushion gas must remain permanently in the storage tank. This maintains the necessary pressure and thus the geomechanical stability; in salt domes it is also necessary for stability. In pore storage facilities, the proportion of working gas in the total volume is around 35 percent, in cavern storage facilities around 75 percent. The usable working gas volume is always specified as the storage size.

gas tank

Above-ground storage facilities are small, but more flexible gas containers made of metal. They are built in low, medium and high pressure tanks: the former mostly in cylinder shape, high pressure tanks in spherical shape or in the bottom as tubular tanks.

Low-pressure vessels (gas towers, gasometers) have 10–50 mbar overpressure, i.e. only a few percent of the air pressure . They are available as wet and dry gas containers.

  • In the case of wet gas tanks, water is used to equalize the pressure; Depending on the functional principle, they include bells , screw and telescopic gas containers . They are simple in design, but have a smaller storage volume.
  • Dry gas containers were developed from 1915 and can hold larger amounts of gas. In the disk gas container, a disk guided in the cylinder moves vertically like a piston. In membrane gas tanks (mainly used for biogas) a membrane takes over this function.

They are also suitable for medium pressures (up to 1000 mbar).

However, with the exception of steelworks and coking plants, low and medium pressure storage systems have lost their importance for the general gas supply .

High pressure tanks are the newer type. As spherical gas containers made of steel, they have a diameter of up to 50 meters and pressures of 5–10 bar (approx. 5 to 10 times the air pressure), with very thick walls up to 20 bar. They are found in large numbers in refineries or for municipal use and, because of their strong compression, they can hold more gas than the earlier gasometers. The first spherical accumulators were built in the 1960s and 1970s for natural and liquid gas and had operating pressures of 2 to 15 bar.

In contrast, tube accumulators can accommodate 50 and 100 bar. They are built a few meters deep in the form of parallel tubes with a diameter of up to 1.6 m. The largest tube storage facility in Europe is located near Volketswil (ZH) in Switzerland , where no geological structures suitable for large underground storage facilities have yet been found.

Individual evidence

  1. ^ BMWi topic page on security of supply , as of December 31, 2014, accessed on April 24, 2017.
  2. RAG storage facilities .
  3. OMV storage facilities ( Memento of the original from May 19, 2014 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.omv.com
  4. Underground gas storage in Germany . In: ERDÖL ERDGAS KOHLE 128th year 2012, issue 11 pdf, 1.54 MB, accessed on April 24, 2017.

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