The Etzel cavern site:

Aerial view of the site
Etzel cavern site showing each cavern
Geometrical cavern volume development

One of the largest cavern sites for ensuring supply

In 1970, the German government decided to store oil for use in a crisis – the so-called federal oil reserve. The salt cavern in Etzel near Wilhelmshaven is one of the locations selected for this purpose.

In early 1971, the mining companies Salzgitter AG/Deutsche Schachtbau- und Tiefbohr-GmbH and Preussag AG founded Kavernen Bau- und Betriebs-GmbH (KBB). The then government-owned industry management company IVG asked KBB to build and run caverns for storing 10 million tonnes of crude oil underground at the Etzel location as part of the federal crude oil reserve.

In autumn of 1973, solution mining operations began in 33 caverns in the Etzel salt dome. Oil filling was completed in 1977. Between 1989 and 1992, nine oil caverns were modified for gas storage and between 1994 and 2004, seven additional oil storage caverns were built. KBB Underground Technologies GmbH played a key role in converting ten additional oil storage caverns for gas storage and subsequent initial gas filling (2006 to 2010).

Since 2006, the Etzel location has become one of the largest gas storage sites in Europe due to the construction of new caverns. The existing infrastructure allows up to 25 caverns to be leached simultaneously. In this expansion project, KBB UT is responsible for completion, gas tightness testing, initial gas filling and snubbing. In 2010, KBB UT has completed 25 new caverns for gas storage operations and initial gas filling as well as the supervision of 23 caverns to be ready for operation. At the moment, the entire location comprises 66 completed caverns (42 gas and 24 oil) with a total volume of 41 million cubic metres (as of July 2013).

For further information see  Storable energy