Reducing greenhouse gas emissions

For every litre of petrol used in a motor vehicle, 2.3 kilograms of carbon dioxide (CO2 ), a major greenhouse gas, is released from the exhaust. The Australian transport sector accounts for around 76 million tonnes of Australia's total net greenhouse gas emissions, representing 13.5 per cent of Australia's total emissions.

Emissions from different fuels

Fuels differ in the amount of carbon and energy they contain as well as other characteristics, with implications for fuel economy and greenhouse emissions. The table below lists the amount of CO2 emitted from the exhaust for each litre of a particular fuel covered by the calculator.

CO2 Tailpipe Emissions/Litre of Fuel Consumed

Fuel Type CO2 Emissions

Petrol 2.3 kg
LPG 1.6 kg
Diesel 2.7 kg

It might seem odd that a greater weight of emissions is produced than the weight of a litre of fuel, but this is because of the addition of oxygen from the atmosphere to the fuel during combustion to form CO2.

This is not the end of the story because it also matters how much fuel is consumed to travel a given distance. LPG has lower greenhouse emissions per litre of fuel consumed than petrol, but also has a lower energy content. Therefore equivalent vehicles tend to consume more of LPG than petrol to travel a given distance. In the case of diesel, its greenhouse emissions per litre are higher than petrol, but engines designed to operate on diesel tend to be far more fuel-efficient than petrol engines. To be sure that one vehicle has lower greenhouse emissions than another use the calculator provided.

You can make a difference

Purchasing a vehicle with low fuel consumption and driving it efficiently can make a real difference to the amount of greenhouse gas emissions it produces. The following table gives an indicative guide to annual CO2 tailpipe emissions from petrol vehicles travelling 15,000 kilometres annually.

CO2 Tailpipe Emissions from Petrol Vehicles

Fuel Consumption Annual CO2 Emissions

6 L/100km 2160 kg
8 L/100km 2880 kg
10 L/100km 3600 kg
12 L/100km 4320 kg