Energy Act (OG 120/12, 14/14, 102/15, 68/18) and General Terms and Conditions of Natural Gas Supply - Addendum 1 Table 3 (OG 50/18, 88/19) prescribe standard natural gas quality.
Monitoring natural gas quality and reporting on it are the legal responsibility of the transmission system operator (TSO), company Plinacro d.o.o., as well as the distribution system operator (DSO), gas storage system operator, liquefied natural gas terminal operator and natural gas supplier.
Natural gas is a fossil fuel which consists of: methane (CH4), which accounts for 85% to 98% of the gas, complex hydrocarbons ethane (C2H6) and propane (C3H8) and higher hydrocarbons, as well as nitrogen (N2), carbon dioxide (CO2) and oxygen, which accounts for between 2% and 15%. The gas is odourless and tasteless, it is highly flammable and explosive.
Standard quality of natural gas that Gradska plinara Zagreb - Opskrba supplies to the end customer is prescribed in the Addendum 1 - Table 3, which is an integral part of General Terms and Conditions of Natural Gas Supply (OG 50/18 , 88/19) All the values relate to the gas volume of 1 m3 in standard condition, in which the absolute pressure of the gas amounts to 101,325 Pa (1.01325 bar) and the temperature of gas is 288.15 K (15°C).
ADDENDUM 1 Table 3 - STANDARD GAS QUALITY (OG 50/18, 88/19)
NATURAL GAS
| A. Chemical composition, mol %: | |||
| Methane (CH4) | min. | 85 | |
| Ethane (C2H6) | max. | 7 | |
| Propane (C3H8) and higher hydrocarbons | max. | 6 | |
| Inert gases (N2 + CO2) | max. | 3 | |
| Carbon dioxide (CO2) | max. | 7 | |
| Oxygen (O2) | max. | 0.001 | |
| B. Sulphur content, mg/m3: | |||
| Total sulphur (S) | max. | 30 | |
| Total hydrogen sulphide and carbonyl sulphide (H2S+COS) | max. | 5 | |
| Thiols (R-SH) | max. | 6 | |
| C. Higher heating value HHV, kWh/m3 | |||
| max. | 10.28 | ||
| max. | 12.75 | ||
| D. Lower heating value LHV, kWh/m3 | |||
| min. | 9.25 | ||
| max. | 11.47 | ||
| E. Upper Wobbe index WI, kWh/m3 | |||
| min. | 12.75 | ||
| max. | 15.81 | ||
| F. Lower Wobbe index Wl, kWh/m3 | |||
| min. | 11.48 | ||
| max. | 14.23 | ||
| G. Relative density d | |||
| min. | 0.56 | ||
| max. | 0.70 | ||
| H. Dew point, °C at a pressure of 70 bar | |||
| water | min. | -8 | |
| hydrocarbon | max. | -2 | |
| I. Gas is non-odorized (apart from the gas in the distribution system), without mechanical impurities, resin or resin-forming compounds. | |||
