Why are there different mixes of propane and butane in LPG (autogas)?
Autogas consists of propane or propane and butane. Residential LPG (used for domestic cooking and heating) consists of propane only. Fluctuations in the relative levels of propane and butane in autogas is not an unusual phenomenon; it is evident in autogas mixes used in other parts of the world, such as Europe. Maintaining different mixes of propane and butane is important for the continuation of the autogas market. The fluctuation provides for the flexibility necessary for the distribution of autogas to metropolitan and regional centres. Certain regional and rural areas are provided with autogas that consists of only propane so that both the domestic and automotive needs can be met with the one tanker load. The environmental gains from placing constraints on the amount of propane or butane in a mix (ie. 50% butane and 50% propane mix) are not significant enough to limit the autogas market to a set composition. Some argue that there may even be environmental gains in allowing the level