History of gas transmission activity in Croatia
The first significant natural gas quantities in Croatia were discovered in 1917 in Bujavica, near Lipik, at the depth of 315 metres. This deposit started to be commercially utilised in 1926 when 500,000 cubic metres were produced. In 1931 an outstanding 6.3 million cubic metres of natural gas were produced. The gas was used to light wagons and to start cars. It was previously compressed into steel containers at 200 bar. Later it was used to produce soot in Methan factory in Bujavica. In 1930 in Gojlo a new gas deposit was found. As a result, in 1937 a new soot factory was built in Kutina, and a year after that, a lime factory, both under the joint name Metan. The gasification of Kutina started the same year. However, due to relatively small gas quantities, there was no interest in its exploration until the discovery of greater field Janja Lipa (1942), oil field Šumećani – Križ (1948) and oil and gas field Kloštar (1951).
This caused the need to transport natural gas to remote customers. In 1954 the construction of the first main gas pipeline from Janja Lipa to Zagreb started, 150 mm in diameter, 98 km long, and it was completed in 1959. However, its first section from Zagreb to Ivanić-Grad was completed by the end of 1955. Therefore, in December 1955, Većeslav Holjevac, the mayor of Zagreb at that time, marked the beginning of utilisation of natural gas as an energy source by opening the valve in the facility Gradska plinara Zagreb. In 1956, from Kloštar to Zagreb approximately 18 million cubic metres of gas were transported, at pressure of 5 to 6 bar. This year was therefore taken as the start of the gas transmission activity in Croatia. Due to inadequate gas preparation for the transmission, the supply to Zagreb was carried out despite technical difficulties and with help of pioneering technical solutions. However, it was already then that the high criteria were set regarding constant and safe delivery and the safety of personnel, assets and environment which today are the basic guidelines for the company’s current business philosophy.
The discovery and production start-up of the gas field Okoli in 1963 was a turning point in the technology of natural gas production, preparation and transmission. The gas transmission system was upgraded from an operating pressure of 25 bar to 50 bar. The higher energy level provided the increase of the system capacity and supply security, creating the preconditions to increase natural gas production and higher quality of its economic and energy evaluation. In the same year, the gas facility Ivanić-Grad was established, a predecessor of today’s Plinacro Ltd. From that year on, the gas transmission activity was developed within Naftaplin.
One of the significant dates in the history of gas transmission development is certainly July 1978, when the international gas pipeline connection Rogatec−Zagreb was put into operation, connecting the gas transmission systems of Slovakia, Austria, Slovenia and Croatia, and thus providing natural gas import into Croatia. Only a year later, in 1979, the first dispatching centre was established, i.e. the system of remote supervision and control of the gas transmission system.