There are basically three types of CNG refuelling stations including fast fuelling stations, slow fuelling stations and combined fuelling stations.

Fast fuelling station – They are fast in fuelling process and takes only five to ten minutes for refuelling. These are ideal for retail roadside pumps.

Slow fuelling stations – They are slow in the fuelling process and may take five to eight hours for refuelling. It is ideal in cases of fuelling the fleet of vehicles that have long idle time.

Combined Fast and Slow fuelling stations – These fuelling stations have the facility of both fast and slow fuelling stations and they cater to both the above categories.

CNG is a compressed natural gas that is stored at compression stations that are connected with the gas pipeline directly. In this case, the gas is compressed at a required pressure that aids in fuelling. It is also possible to transport CNG to other retail outlets by using the cylinder trucks. These trucks carry lots of cylinders that provide CNG to fuel stations that are not connected by pipelines. These fuelling stations are usually placed alongside petrol and diesel pumps.

Bi-fuel Possibility

It is possible to operate the vehicles in the dual mode such as Petrol-CNG and Diesel-CNG. Thus, vehicles can be run on either petrol or on CNG.  There are many companies that have used this dual mode experiments successfully such as Kirloskar Cummins Ltd, Ashok Leyland, IBP, Delhi Transport Corporation, TELCO, OIL, and Gujarat Road Transport Corporation.

The Gas Authority of India Limited (GAIL) has proposed the use of CNG for vehicle manufacturers to undertake conversions on their vehicles. The actual performance of the vehicles can be monitored by Indian Institute for Petroleum. There are large reserves of natural gas in many countries around the world. It is likely that CNG would soon replace the petroleum products as dominant fuel.