# How is gas measured

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### What does the calorific value say for natural gas?

The calorific value shows the specific quality of the natural gas. The value is given in kilowatt hours per cubic meter (kWh / m³) and must be included in every gas bill. The higher the calorific value, the more energy natural gas has.

The reason for specifying the calorific value is the differences in quality of the natural raw material natural gas. Gas from Russia has a different composition and therefore a different calorific value than natural gas from North Africa. In principle, a distinction is made in Germany between the two natural gas qualities H-gas and L-gas.

H gas: H stands for high and has a high calorific value. This is between a factor of 10 and 12. H-gas is produced in Russia or the North Sea, for example.

L gas: or low gas has a lower calorific value of 8 to 10. This natural gas is produced in northern Germany or the Netherlands.

The natural composition of the gas defines the calorific value. Natural gas consists mainly of methane. However, it is also made up of weakly reactive gases such as nitrogen and carbon dioxide. The higher their proportion in the gas mixture, the lower the calorific value. The quality of the natural gas depends on the location and is charged according to the legal standards with the help of the calorific value on the consumption bill at a uniform gas price per kilowatt hour.

The calorific value is listed on every gas bill or can be requested directly from the gas supplier.

Figure 2: Example of gas billing

### What is the state number (z-number)?

The condition number describes the ratio of the natural gas volume in a previously defined standard condition to the gas volume in the operating condition.

The pressure and temperature that prevail when the gas is drawn off affect the volume of the natural gas supplied. The condition number takes these local influences into account and offsets them with the standard condition, which is defined for natural gas at 0 degrees Celsius and around 1 bar pressure.

The condition number is listed on every gas bill and can be added together with the amount of natural gas consumed and the calorific value to form the total consumption, which is given in kilowatt hours.

Figure 3: Example of gas billing

### No change in quality due to a change of supplier

Germany is divided into four different natural gas supplier zones, in which households are supplied with either L-gas or H-gas. The end consumer does not notice the difference, however, as the household suppliers calculate the different gas quality and the individual network areas to a uniform quality level in accordance with legal requirements. This means that the quality or the condition number of your natural gas always remains the same, even if you change gas provider.