Portrait:

Haidach always had a hidden treasure. Exactly ten year ago the biggest find of natural gas since 1982 was made in the fields around the small hamlet at the border between Upper Austria and Salzburg (municipality of Seewalchen). More than 2.9 billion m³ of the precious source of energy have been extracted from the Flachgau soil for the Austrian market since the start of production in 1998. This represents nearly one third of the Austrian annual natural gas consumption. The natural gas reservoir was discovered in 1997 through the use of high-tech geophysical methods by the Rohöl-Aufsuchungs AG (RAG), the oldest mineral oil company of Austria.

In 1936 RAG was already pumping the first Austrian oil from the ground in Zistersdorf. Nowadays the company has concession areas with centres in the Upper Austria and Salzburg alpine foothills and the Bavarian Chiemgau. The output contributes to the fact that Austria can meet about 20% of its requirement of natural gas of nearly 10 billion m³ from the depths of its own land.

Dipl.-Ing. Markus Mitteregger, RAG

From empty to full

In Haidach RAG made use of a unique geographical and geological constellation: Nature itself had been storing natural gas for more than 20 million years in Haidach at depths of over 1 600 metres and sealed it with mighty layers of clay. Now, after the naturally available gas has been extracted, this natural deposit area will become Austria’s biggest natural gas reservoir. With investments of more than 250 million Euro the area will store up 2.4 billion m³ of natural gas when it is completed. This will double the national storage capacities of at present 2.5 billion m³. Haidach is the second largest reservoir in Europe after Rheden in the Federal Republic of Germany, where the German WinGas can store up to 4 billion m³. WinGas is together with Gazprom and RAG the third partner in the development Haidach.

With the new storage volumes Austria can extend its natural gas reservoirs from 30 % to nearly 50 % of its annual consumption. The country thus has the softest pillow of all EU states to rest on. Germany can only store 22 % of its annual consumption, France 26 %. According to EUROSTAT the natural gas oriented states of Slovakia (38 %) and the Czech Republic (32 %) were the storage champions of the EU so far.

Markus Mitteregger, director in charge of the RAG business sector of natural gas storage, calls the new natural gas reservoir “a milestone for energy security of Europe and thus of Austria.

In future the RAG business sector of natural gas storage would clearly be accelerated abroad too.

Natural gas reservoirs strengthen security of supplies

Natural gas reservoirs balance the daily fluctuations of natural gas consumption. In winter twice the amount of the consumption on an average summer day must be fed into the national grid. The gaseous energy source is however supplied on the basis of long-term contracts with a constant bandwidth. In view of the high import demand of more than 80 % – 60 % come from Russia, the rest from Norway and Germany – the interim storage of natural gas in underground reservoirs is indispensible for a secure natural gas supply. ”Contrary to other European countries Austria is lucky to possess excellent geological conditions for natural gas reservoirs. In Austria we store twice the amount of natural gas than the EU average“ states RAG director Mitteregger. The geostrategic position of the reservoir in Upper Austria is of central importance for this: Haidach is linked by a 39 km long pipeline with a diameter 900 mm to the German-Austrian natural gas hub of Burghausen/Überackern which secures access to all important European supply grids for natural gas.

RAG uses a specific advantage of the Austrian geology in Haidach. The re-use of exhausted deposits as natural gas reservoirs is only possible in a few regions in Europe. “We are at present with the help of expert studies examining very carefully which Austrian deposits are still suitable for re-use as natural gas reservoirs. The future of energy security in Europe depends last not least on the possibility of having natural gas in store”, Mr Mitteregger outlines the future plans of RAG. The constellation of the property rights of the reservoir remains interesting. The Austrian natural gas deposits are the property of the Austrian state. The state contractually transferred the user rights for the Haidach deposit to RAG. RAG is bound to use and exploit them against payment of rent as best as possible and sustainably.

Premium project for TÜV

The first stage of the extension of the Haidach reservoir was projected and implemented in two years. More than 300 specialist from all over Europe were involved in it with more than one million working hours. The experts of TÜV AUSTRIA were also engaged right from the beginning. Staff from our Linz and Salzburg offices shared the tasks and was on site during the entire building phase. Peter Exenberger, the person in charge of the project for TÜV, describes Haidach as “one of the most challenging projects of the last years. We are proud that the works and the start of operations went so smoothly. TÜV was commissioned by the awarding authority with the assessment of the entire assembly: This was a comprehensive concept to organise an installation consisting of individual appliances and individual parts safely into a functioning ensemble. The assemblies for the Haidach project comprise numerous separate fields of application requiring technical knowledge from very different technical areas. The reliable assessment of the overall safety of such units can therefore only be achieved by a group of experts. “The Haidach project was a perfect example for the interaction of colleagues from different fields and genuine teamwork between Linz and Salzburg“, enthuses Christian Braun, head of our Linz office.

TÜV Austria was also in charge of the safety inspection of the installations before commissioning. The scope ranged from the initial inspection of all pressure equipment of the installation to the tightness test of the many kilometers of pipelines. RAG director Mitteregger: “The protection of the environment and utmost occupational safety are our most important concerns. The Haidach natural gas reservoir was built according to the highest environmental and safety standards and will be operated in future in exactly the same manner.”

IDEAL CONDITIONS

The Haidach natural gas deposit is a “textbook deposit“ regarding its re-use as a natural gas reservoir. It extends over 17,5 km2, the sandstone in whose pores the natural gas is stored, has a thickness of about 100 m and there are layers of clay above it. The actual storage does not take place in cavities, but in solidified sandstone structures with innumerable intertwined pores in which the natural gas is stored. The gas is pumped into the rock for storage. Because of the high permeability of the storage rock about one million cubic metres per hour of natural gas can be taken from the reservoir.