7Fields was planned and built by RAG under its concession.
Since then, RAG has been technical storage operator. The German Uniper Energy Storage has a holds a share of 50% of 7Fields. The first expansion phase began in 2009 and was completed in 2011. Following completion of the second expansion stage in 2014 and a capacity adjustment in 2019, around 2.1 bn cu m (24,2 TWh) of natural gas can now be stored at 7Fields. It has an injection capacity of 689,300 cu m/hour (11.9 GW) and a withdrawal capacity of 1,033,900 cu m/hour (11.9 GW). 7Fields is made up of former gas fields in Upper Austria and Salzburg. Integration of several storage reservoirs into an interconnected storage facility is particularly resource efficient. The site is unique in Europe, with five storage stations connected via pipelines to three metering stations and to the Austrian and international gas grids. Uniper and RAG Energy Storage market the capacity of this interconnected storage network.
