Quality of natural gas

In order to be sure that you are using the best quality gas, suppliers are obliged to meet strict provisions concerning the quality of delivered gas.

„The quality of natural gas is dependent on the technical demands for the quality of natural gas supply, while the adherence to these demands on the part of the operator of the natural gas system ensures that the user of the system or the end-buyer is guaranteed that the parameters of the quality of gas are in compliance with the standards for gas quality“ (General conditions for gas supply, Official Gazette number 158/13)

PLINACRO (the state operator of the natural gas transport system) carries out continuous controls of the gas entering the transport system of the Republic of Croatia. It receives natural gas from a number of different sources, ranging from gas from Croatian gas fields, to imported gas from Russia, Italy, the Netherlands, Algiers and other countries. Gas enters Croatia in two spots – through interconnections in Slovenia (Rogatec) and Hungary (Drávaszerdahely). The quality of the natural gas is measured at both of these entry points (so-called specific points) into the Croatian natural gas transport system, in order to prevent the possibility that gas entering the system does not meet the required quality standards.

The state operator of the natural gas transport system, Plinacro, publishes regular reports concerning the quality for both specific points on its web pages.

With respect to the quality of the natural gas, the most important element for end-users is the lowest level of the heat rate of the gas, namely the heat that is freed by the combustion of this energy source. In the Republic of Croatia there has never been an instance where the heat rate was below the defined standard level.

The quality of the natural gas cannot be measured on the basis of the colour of the flame in the consumer's appliance since the colour can depend on several factors. Natural gas is a mixture of various hydrocarbons, for the most part methane (CH4), but the composition of the other hydrocarbons (ethane, propane, butane and traces of heavy hydrocarbons) can vary without affecting the heat rate of the natural gas while at the same time causing changes in colour while burning in the appliance. Furthermore, the colour of the flame also depends on whether there is dirt on the burner or on whether the nozzle is properly adjusted or not. Although the ideal mixture of air and natural gas gives off a blue flame, if there is not enough air, the gas will burn with yellowish or reddish hues, depending on the types of hydrocarbons present.