What is Compressed Natural Gas?
CNG represents a convenient form of natural gas that is half way between the gaseous and liquid states. That is to say, for a given volume, it has more energy than the original gas, though not as much as the liquid gas. Natural gas has a low specific energy, and for example, a litre of diesel fuel has as much energy as 1000 litres of natural gas. But if natural gas is compressed to 200 times normal atmospheric pressure – to some 3000 lb/in2, the equivalent storage volume comes down to just five litres. However, if the gas is compressed even more, it eventually liquefies, and the volume decreases yet again, to just two litres. Both LNG and CNG systems provide a rapid fill facility and are pilfer proof.
