The Haidach gas reservoir in the state of Salzburg owns primary porosity and was found by Rohöl-Aufsuchungs Aktiengesellschaft (RAG) in 1997 at a depth of 1600 meters. It was converted into one of the largest underground gas storage facilities in Central Europe by WINGAS, RAG and Gazprom export.
The operations of the UGS started on the 1st of July 2007, with the usable working gas volume of 1,2 billion m3. Upon commissioning of Stage II of the UGS facility on the 1st of April 2011, its usable working gas volume totaled 2,64 billion m3. At the moment it is 2,9 bcm. (available storage capacity)
The Austrian underground storage facility Haidach comprises the utilization of the reservoir and connecting the storage facility to the German/Austrian gas terminal at Burghausen. So it can be used consequently in Germany also Austria for the seasonal balance.
The connection is graphically shown on the map below. See more detailed information about storage characteristics at this link.