CNG (Compressed Natural Gas)

CNG stands for Compressed Natural Gas, which refers to natural gas compressed at around 200 to 250 bar. It significantly reduces emissions and can come from fossil fuels or renewable sources (bio-CNG).

Definition of CNG
CNG is a fuel obtained by compressing natural gas and stored in high-pressure tanks. The fuel is characterized by a high energy density and reduced emissions compared to conventional fuels.

Background / Origin
CNG has become increasingly important in the automotive industry due to its properties. The use of CNG as a fuel enables a significant reduction in environmental pollution through reduced emissions of carbon monoxide, nitrogen oxides and CO2. Bio-CNG from processed biogas can, depending on the source and comparison basis, enable lower CO2 emissions than conventional fuels.

In 2010, the German government presented an energy concept that promotes the use of CNG and Bio-CNG. This promotion is reflected in more favorable taxation compared to petrol and diesel in order to increase the attractiveness of CNG as an alternative fuel. The international standardization and the associated quality framework are defined in DIN EN 16723-2.

Properties
CNG consists mainly of methane and has the following physical characteristics:
- Compressed to approx. 200 to 250 bar.
- Gaseous and lighter than air.

The quality differences between CNG are divided into H-gas and L-gas:
- H-gas: Higher energy content (approx. 20% above that of L-gas).
- L-gas: Lower energy content.

The chemical characteristics of CNG include
- Low emission levels: reduction of carbon monoxide by up to 80%, nitrogen oxide by up to 80% and CO2 by up to 25%.
- Bio-CNG can enable lower CO2 emissions than conventional fuels, depending on the feedstock, production pathway and comparison basis.

The quality requirements are determined by DIN EN 16723-2, which defines properties such as calorific value, density, methane number and content as well as limit values.

Application and importance in the market
CNG is used as a fuel for vehicles that must be equipped with special high-pressure tanks. Its particular importance results from fuel properties such as lower emissions in certain comparisons and its use in suitable vehicle applications.

International differences in the use and availability of CNG exist in the gas quality, which depends on the regional network and local standards. CNG is also offered via filling stations, such as those of OIL!, which increases accessibility for consumers.

Differentiation from similar terms
CNG differs from Liquefied Petroleum Gas (LPG) in the following aspects:
- Storage: LPG is stored in liquid form at 8-10 bar, whereas CNG is compressed in gaseous form up to 250 bar.
- Density: LPG is heavier than air and can remain as a puddle in the event of an accident, whereas CNG is lighter than air and evaporates.

Summary
CNG, as compressed natural gas, offers high energy density and can have lower emissions than conventional fuels depending on the product, source and comparison basis. It can come from fossil or renewable sources, with bio-CNG offering significantly lower CO2 emissions. International standardization and promotion through government programs increase its relevance in the market. Quality requirements are regulated in DIN EN 16723-2 and the distinction from LPG clarifies the safety-related differences.