Underground gas storage in the Czech Republic
The Czech Government has decided to expand the volume of underground gas storage tanks to cover 50 percent of the country's annual consumption. The Minister of Industry and Trade, Jan Mládek, made this statement at a recent international energy conference in Ostrava.
At present, the Czech Republic's storage tanks have a capacity that can cover approximately 37 percent of the country's annual natural gas consumption. The gas is stored in nine underground storage tanks with a total capacity of 2 931 million cubic meters. Given the size of the economy, it is one of the largest storage capacities in Europe. The capacity should be increased to 3 700 million cubic meters by 2021.
Gas storage facilities form an important part of the gas infrastructure, since they are used to compensate seasonal variations in natural gas consumption: in summer months, the gas is usually stored, and then it is withdrawn to cover the increased gas consumption in winter. Gas tanks also increase the energy safety of the country and serve economic purposes too, since gas is cheaper in summer than in winter.
The Czech Republic has certain suitable rock structures that can potentially be used as gas reservoirs. The Government commissioned a project aimed at determining the exact location of the most suitable rock structures that could be used for storing gas.
The project assignment was based on the growing importance of natural gas storage from the perspective of both national economy and strategy of the state. Another objective was to develop a methodology for determining suitable rock structures for underground gas tanks, and monitoring the impact of such tanks on the environment. The study showed that the natural conditions of the Czech Republic only offer limited possibilities for building underground gas reservoirs. Suitable places include only selected sites of crystals of the Bohemian Massif and hydrocarbons deposits which have been abandoned after extraction or the extraction of which is coming to an end, especially in the Vienna Basin and Carpathian Foredeep. Another important aim of the study was to verify the possibility of increasing the capacity of existing underground tanks, which seems to be difficult to implement. Based on the evaluation of the to-date course of storage, one can say that low-volume increases have already been made in all long-term operating tanks, and any further increase would be minimal. It is therefore recommended to increase the capacity of gas tanks through medium and large volumes (i.e. construction of new tanks) as well as amendments to existing legal norms.
The oldest reservoir of natural gas in the Czech Republic is a tank in Lobodice, whose construction began as early as 1962. The gas infrastructure is currently expanding; two new tanks are being built in Rožná and Dambořice. Also the capacity of the existing reservoirs is being increased – for instance, the Tranovice tank capacity rose to 530 million cubic meters in 2012. Eight of the existing tanks belong to RWE Gas Storage and MND Gas Storage. The data provided by the Council of the Czech Gas Association show that Czech gas companies invested three billion Czech crowns (approximately 110 million EUR) into tanks expansion.