Storing natural gas

Given Austria's geological set-up, the only type of underground storage available are pore storage facilities. As opposed to cavern storage sites that are mostly used to cover peaks, pore storage is particularly useful to balance seasonal consumption swings.

At the time of liberalisation, the only two storage system operators active in Austria were OMV and RAG. New storage capacity has been created in RAG's concession area, with RAG operating the facilities but not acting as storage undertaking in these cases. This type of cooperation was first applied when the Haidach storage facility was commissioned in 2007: RAG acts as the operator, Wingas GmbH & Co KG and Gazprom Export as marketers. The model was repeated in 7-fields, where RAG again is the operator of the facility but marketing is handled by Uniper Energy Storage (formerly known as E.ON Gas Storage). This type of cooperation has meant that there are now three more storage undertakings that market products on the Austrian storage markets.

The transposition of Article 15 of Directive 2009/73/EC into national law meant legal and organisational unbundling for storage system operators. Storage system operators' independence must be guaranteed through measures such as separation from the vertically integrated undertaking in terms of company law, sufficient resources, de facto independence of executives, establishment of a compliance programme and a compliance officer, and the confidential treatment of sensitive business information. The unbundled storage undertakings that now market capacity in Austria are: astora GmbH & Co KG, Uniper Energy Storage GmbH, GSA LLC, OMV Gas Storage GmbH, and RAG Energy Storage GmbH.

The Gaswirtschaftsgesetz (Natural Gas Act) 2011 also introduced new rules for system utilisation by storage system operators: since 1 January 2013, storage system operators have had to book the maximum storage entry and exit capacity that they need during the next calendar year with the system operator once a year.

Since 2010, storage capacity has been significantly increased through the expansion of 7Fields, Haidach, and Aigelsbrunn. Thus, the increase of the working gas volume from 2010 to 2015 was around 81%. Following the shutdown of the Thann storage facility on 1 April 2017 for investment reasons, the total working gas volume in November 2018 was 92.2 TWh and then rose to 92.8 TWh due to the capacity increase at the Haidach storage facility as of 1 April 2019 and to 93.6 TWh due to the capacity increase at the 7 Fields storage facility as of 1 October 2019.
Also in 2019, capacity was reallocated in the 7Fields storage facility, whereby RAG Energy Storage GmbH now also holds storage capacity there, in addition to Uniper Energy Storage GmbH. At the same time, data of the Nussdorf/Zagling storage facility is reported together with the 7Fields storage facility and no longer separately. This is not least due to the organisational changes mentioned above, as the Nussdorf/Zagling storage facility has been part of 7Fields since the beginning.

Due to additional drilling, there was a capacity increase in both the Haidach and in the 7Fields storage facility in 2020. In Haidach, capacity was increased by around 1.4 TWh as of 1 April 2020 and divided between the two capacity marketers GSA LLC (1/3) and astora (2/3). The additional injection rate of 563 MWh/h in total was allocated to the two storage undertakings in the aforementioned ratio. In 7Fields, storage capacity increased by 0.6 TWh as of 1 August 2020, 100% of which was taken over by RAG Energy Storage for marketing. Hence, this results in a total working gas volume of 95.5 TWh at the end of 2020.

With approx. 26% (25.2 TWh) working gas volume, OMV Gas Storage continues to have the largest share in storage capacity in relation to Austria and with approx. 40 % in relation to the storage facilities connected to the Market Area East.
The Haidach storage facility does not currently have a direct connection to the market area but is instead filled through the German gas network; it is possible to use these gas volumes for the Austrian market, where they appear as imports. In addition, the Slovak storage site LAB is connected to the virtual trading point through the MAB line; the storage system operators for this facility are Nafta and Pozagas.

Storage capacities in Austria, November 2020

Storage system operator/ Storage Injection rate in MWh/h Share of total injection rate Withdrawal rate in MWh/h Share of total withdrawal rate Working gas volume in MWh Share of total working gas volume
OMV Gas Storage Schönkirchen 7.345 20,95% 10.848 24,59% 20.720.000 21,70%
OMV Gas Storage Tallesbrunn 1.413 4,03% 1.808 4,10% 4.520.000 4,73%
OMV Gas Storage in total 8.758 24,98% 12.656 28,68% 25.240.000 26,43%
RAG Energy Storage Puchkirchen/Haag 5.900 16,83% 5.900 13,37% 12.200.000 12,77%
RAG Energy Storage Haidach 5 227 0,65% 227 0,51% 181.000 0,19%
RAG Energy Storage Aigelsbrunn 567 1,62% 567 1,29% 1.500.000 1,57%
RAG Energy Storage 7Fields 1.700 4,85% 2.600 5,89% 6.200.000 6,49%
RAG Energy Storage in total 8.394 23,94% 9.294 21,06% 20.081.000 21,03%
Uniper Energy Storage 7fields 6.082 17,35% 9.123 20,67% 17.515.000 18,34%
Storage Capacity Market Area East in total 23.234   31.073   62.836.000  
Astora Haidach 4.132 11,79% 4.344 9,85% 11.345.133 11,88%
GSA LLC Haidach 7.694 21,95% 8.708 19,73% 21.318.900 22,32%
Storage Capacity Austria in total 35.060 100,00% 44.124 100,00% 95.500.033 100,00%

17 November 2020; Sources: Websites of the storage system operators,