MFGT has four underground storage facilities in Hungary with a total annual working gas storage capacity of 4.43 billion cubic meters. Daily maximum withdrawal capacity is approximately 53.6 million cubic meters, which can cover more than 55% of the daily peak gas demand during the winter period.

 
Working gas by definition is the natural gas reserve which is injected into the underground storage facilities each year from April to October to be withdrawn during the winter period.
 
Zsana
  • Working gas capacity: 2170 mcm
  • Withdrawal capacity: 28 mcm/day
  • Injection capacity: 17 mcm/day
 
Hydrocarbon exploration started in the vicinity of Zsana village in 1978. Over the ten years between 1982 and 1992, approximately 4 billion m3 of natural gas was exploited from the gas reservoir in Zsana.
 
The construction of the Zsana Storage Site began in 1992. The initial storage capacity of the storage site was 600 million m3 and the first withdrawal was carried out in November, 1996, with a daily withdrawal capacity of 8 million cubic meters. Owing to its geological characteristics (limestone reservoir), the Zsana Storage Site is the most flexible natural gas storage facility of our country. At a depth of 1695 – 1780 m below sea level, 4 layers take part in storing natural gas.
 
As a result of capacity expansions carried out in several stages by 2008, the capacity of the storage site was increased to 1,570 million m3 with a withdrawal capacity of 24 million m3/day and a peak injection capacity of 10.2 million m3/day.
 
In the summer of 2008, E.ON Földgáz Storage commenced further expansion of the storage site within the framework of a project amounting to a total of HUF 32 billion. The extension was completed on time, by the autumn of 2009, increasing the capacity of the storage site by 600 million cubic meters to almost 2.2 billion. The daily withdrawal capacity now reaches 28 million cubic meters per day. The injection capacity has also been considerably enlarged, up to 17 million m3/day, owing to the new turbo compressors.
 
Hajdúszoboszló
  • Working gas capacity: 1640 mcm
  • Withdrawal capacity: 19.8 mcm/day
  • Injection capacity: 10.3 mcm/day
 
Hajdúszoboszló used to be the most important source of natural gas in Hungary. The era of natural gas started in Hungary by exploiting the sources explored in the fifties. During the peak period of natural gas production, i.e. from the end of the sixties, 1.8 billion m3 of natural gas was exploited annually from the gas field in Hajdúszoboszló.
 
The establishment of the facility begun in 1977. In 1981, the storage site’s 35 wells equipped with special sand filter were able to store 400 million m3 of working gas.
 
During several development projects, working gas capacity was expanded to 1400 million m3. The reconstruction work to maintain the existing capacities in the long run started in the nineties.
 
Currently, the nominal working gas capacity of the storage site is 1,640 million cubic meters, with a daily withdrawal capacity of 19.8 million m3 and a daily injection capacity of 10.3 million m3.
 
Pusztaederics
  • Working gas capacity: 340 mcm
  • Withdrawal capacity: 2.9 mcm/day
  • Injection capacity: 2.5 mcm/day
 
Pusztaederics Storage Site is operated in sandstone formed in the Lower Pannonian Period (upper and lower Nova reservoirs, Szolnok Sandstone Formation). The storage facility was established by utilizing the former Hahót-Ederics depleted natural gas field.
 
Over the period between 1972 and 1979, five former natural gas production wells were used to store natural gas and the Pusztaederics facility had become the very first storage site in Hungary.
 
By 1979, additional 7 wells were completed and the facility was officially classified as a storage site. At that time, the total working gas capacity of the 12 wells amounted to 100 million cubic meters. In 1988, this capacity was increased by 100 million cubic meters of gas, then in 1991 additional new wells were put into operation as a result of further developments.
 
Currently, the nominal working gas capacity is 340 million cubic meters. The daily withdrawal capacity is 2.9 million m3, while the daily injection capacity is 2.4 million m3. The volume of the cushion gas that facilitates seamless operation for the storage site is 266 million m3. The Pusztaederics Lifetime Extension project was finished recently, to ensure the future operation of the site.
 
The Pusztaederics facility is the only storage site in the Transdanubian region, therefore it plays an important role in maintaining the hydraulic balance in the high pressure pipeline system in the western part of the country.
 
Kardoskút
  • Working gas capacity: 280 mcm
  • Withdrawal capacity: 2.9 mcm/day
  • Injection capacity: 2.15 mcm/day
 
In 1960, a natural gas field containing slightly more than 1 billion cubic meters of exploitable gas was found around Kardoskút and Pusztaszőllős. The exploitation started in 1966.
 
After the gas reservoir was emptied, its utilization for storing natural gas started in 1978 with just 7 wells. In 1984, the aboveground facilities and the injection capacity were enlarged, and a number of new wells were drilled in the subsequent 4 years. The average depth of the sandstone reservoir suitable for storing natural gas is 1000 – 1100 m.
 
Currently, Kardoskút Storage Site operates with 21 production wells and 8 observation wells. Its present working gas capacity is 280 million cubic meters, while the withdrawal capacity is 2.9 million cubic meters per day.