AUTOGAS:
Effective, available, Universal
The advantage of LPG is, that it is non-toxic, does not cause corrosion and has a high octane number (102-108, depending on local specifications). It burns cleaner than gasoline or diesel and does not emit soot.
LPG has a slightly lower energy density, than gasoline or diesel, so the equivalent fuel consumption is slightly higher. Many governments impose lower taxes on LPG, than on gasoline or diesel, which helps increase its consumption at the expense of other fuels. LPG is the third most widely used motor fuel in the world. For 2008 the grades are, that over 13 million vehicles worldwide use LPG. Above 20 million tons (over 7 billion. US gallons) annually are used as fuel.
Comparison with natural gas
LPG is mainly composed of propane and butane, while natural gas contains mostly methane and ethane. It has a higher calorific value (94 MJ / m 3 , equivalent to 26.1kWh / m³) from natural gas (methane) (38 MJ / m 3 , equivalent to 10.6 kWh / m 3), which means, that it cannot be easily replaced by natural gas.
Impact on the environment
Commercially available LPG currently comes mainly from fossil fuels. When it is burned, carbon dioxide is released, which is a greenhouse gas, but its amount is minimal and does not contribute to global warming. LPG emits only 81% of carbon dioxide per kilowatt hour, which is released when oil is burned, and 70% than that for coal. It can be considered a more environmentally friendly fuel than liquid fuels, because it emits very few particles (soot) when burning.
Fire hazard and risk reduction
Because LPG is a gas at room temperature and pressure, it must be stored in special pressure vessels. They are usually full between 80% and 85% of its capacity, to allow for thermal expansion of the contained liquid. Propane-butane containers, which are subjected to fire of sufficient duration and intensity, can explode, because the pressure rises significantly. This is usually a problem for large refineries and petrochemical plants, who own very large tanks.