Compressed natural gas (CNG)Introduction

Compressed natural gas is basically methane stored at high pressure that is compressed to 1% of its volume. It is used in place of petrol, diesel or LPG in a combustion engine to produce energy. CNG is collected from oil deposits, landfill sites and wastewater treatment plants. It is stored in cylinders at a pressure of 20–25 MPa.

Market for CNG

International CNG demand was 61,668 MCM 4 years ago and the compressed natural gas market is expected to reach 108,957.9 MCM in another 4 years. Light duty vehicles are the biggest consumers of CNG. With the growth of passengers and the government support the compressed natural gas (CNG) market is expected to reach USD 129.77 billion by 2020.

Strict Emission Control Norms and the low cost of CNG when compared to LPG and other fuels are the main growth driving factors of the CNG Market. However these factors are sometimes nulled by the high initial cost of acquiring the CNG equipment and setup.

Advantages associated with using CNG as a fuel

  • The vehicles which use CNG have generally low maintenance costs.
  • Due to the sealed fuel storage there is no loss of fuel due to a spill or through evaporation.
  • It has a very ignition temperature of around 540 0C and due to a very low flammability it greatly reduces the chance of accidents.
  • CNG produces lesser amount of pollution when compared to other fuels. It does produce CO2, CO,NOx,SOx, and particulate matter but in considerably low amount.

Disadvantages of using CNG as a fuel

  • Since it is compressed form of gas and not a liquid, CNG occupies greater space than other fuels like petrol. Thus a larger space is required to for fuel storage while using CNG.
  • Natural gas leaks while filling the cylinders, transporting the fuel or directly from the source has been recognized as an increase in greenhouse gas emissions.

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International guidelines

Currently there are no International standards for the use of CNG but even then the accidents that occur due to CNG mishaps are negligible in comparison to other types of fuel. However the CNG cylinders nozzles for vehicles follow ISO 14469-2:2007 standard and the pressure regulatorare needed to pass the tests given in ISO 15500-9:2012. ISO or The International Organization for Standardization has been working in the direction of setting the proper guidelines for a few years.


Vehicles which use CNG as a fuel mainly run in developing countries, due to its cost effectiveness against other fuels. CNG is used in auto-rickshaws, pickup trucks, school buses etc. With the increase in its use, the cost of fuel storage has been lowered and more and more people are adapting to its use as a cleaner and cheaper source of energy.