LPG isn’t just for cab drivers and grey nomads. Cheaper and cleaner than petrol, it’s also powering a new generation of desirable cars
LPG, or Autogas (the generic name) is usually a mixture of propane and butane. Domestic gas is propane only but, confusingly, some regions and remote areas receive propane-only LPG via tanker for both automotive and domestic use.
LPG is found along with natural gas and condensate in offshore wells – Western Australia has the greatest known reserves – and is also a byproduct of oil refining.
There is no set proportion of propane to butane and the mix depends on how and where the gas is recovered.
The environment.gov.au website notes: ‘‘The environmental gains from placing constraints on the amount of propane or butane in a mix (i.e., 50 per cent butane and 50 per cent propane mix) are not significant enough to limit the autogas market to a set composition.’’
Unlike liquid natural gas (methane), LPG needs little pressure to convert from a gas to a liquid and doesn’t have to be refrigerated to remain in that state.
LPG’s energy content (the amount of energy released during combustion) is about 25 per cent lower than petrol, releasing between 25.7 and 34.2 megajoules a litre.
Fuel consumption increases by about the same percentage.