Thanks to its high energy density and low emission values, it is a good fuel for powering vehicles, provided they are equipped with a suitable high-pressure tank.
The natural gas arrives at the station at a low pressure from a local gas (utility) line.
An underground compressor then takes that fuel and compresses it to a higher pressure.
After the compression of the natural gas, the CNG is then transferred to storage vessels so that the fuel is readily available.
CNG is inexpensive to produce and store making it ideal for numerous fleet sizes: refuse trucks, buses, shuttles, taxis and heavy-duty trucks.
Using CNG as fuel reduces:
- carbon monoxide and nitrogen oxide emissions by up to 80%
- CO2 emissions by up to 25%,
- the proportion of methane hydrocarbons by up to 73%
But it can also consist of refined biogas, and come from renewable energy sources, in which case it is called bio-CNG and reduces CO2 emissions up to 85%.
Another advantage of CNG is that its processing into a fuel doesn’t require any additives or complicated refining processes.
CNG is not to be confused with liquefied petroleum gas (LPG).
The main difference between these gases is that LPG is stored as a liquid, fuelled at 8-10 bar, and is heavier than air.
CNG is compressed to 250 bar and is gaseous and lighter than air.
That means that in case of an accident or leak, LPG remains as a puddle on the floor and represents a danger, while CNG rises and evaporates.