Why do LPG models get a better Greenhouse Rating than the equivalent petrol model, even though their fuel consumption is higher?
Carbon dioxide (CO2) is the major greenhouse gas from transport, and thus the Greenhouse Rating is based on the rate of CO2 emissions from the vehicle, not the litres of fuel consumed. The amount of CO2 emitted when a litre of fuel is burned differs depending on the type of fuel. A vehicle using LPG, will have a higher fuel consumption (in L/100km) than the same vehicle using petrol. This is due to the difference in energy content between LPG and petrol. However, when a litre of LPG is used by a vehicle, the level of CO2 emissions from the exhaust is significantly lower than that for a litre of petrol, because of the lower proportion of carbon in LPG relative to petrol.
