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The different car fuel options

There are several different fuel options for cars. These include:

• petrol
• diesel
• liquefied petroleum gas (LPG)
• compressed natural gas (CNG)
• petrol/electric or ‘hybrid’ cars

Use the car fuel data tool to find out which models of cars use which fuel.

• Car fuel data, CO2 and vehicle tax tools Opens new window

Petrol and diesel cars

The different fuels have different merits from an environmental point of view. Diesel engines have significantly lower carbon dioxide (CO2) emissions per kilometre travelled than petrol engines. This is because of the higher efficiency of the diesel engine, which means they have a lower impact on climate change.

Diesel cars also emit lower levels of carbon monoxide (CO) and hydrocarbon (HC) than equivalent petrol cars. However, diesel engines emit greater levels of oxides of nitrogen (NOx) and more tiny soot particles than new petrol engines. This can negatively affect air quality in urban areas.

LPG and CNG cars

LPG and CNG cars are generally converted from petrol-fuelled cars. For practicality, LPG and CNG cars tend to be bi-fuel, meaning that they can run on either petrol or the gaseous fuel.

LPG cars tend to fall between petrol and diesel in CO2 performance. This is because of the lower carbon and higher energy content by mass of the fuel. CNG offers even lower CO2 emissions than LPG, typically comparable with diesels.

The pollutant (CO, HC, NOx and particles) emissions of well-engineered LPG and CNG cars are similar or slightly better than those of petrol cars.

Petrol/electric or 'hybrid' cars

Hybrid cars combine an internal combustion engine with an electric motor and battery. There are many ways that the hybrid car can work. For example, the car may be able to operate:

• solely on its engine
• solely on battery power
• a combination of the two

If the car uses a combination of the two, the battery power will give extra power during acceleration and when the engine is required to work harder. The battery can then be recharged by the internal combustion engine or from energy absorbed during braking. In some cases, it is also possible to recharge the battery using an external electrical supply. Hybrid cars can offer reduced fuel consumption and CO2, and may also help to reduce air pollution in heavily congested areas.

Biofuels

Biofuels can offer a way to reduce the impact of cars on climate change. The fuels are not entirely CO2 neutral because of the energy used to grow and process crops from which they are made, but they can offer substantial CO2 savings.

Most biofuels sold are mixed with petrol or diesel. Up to 5 per cent of the biofuel can be mixed with petrol or diesel, and these mixes are suitable to use in all cars. Fuel standards may be extended in the future to allow more than 5 per cent if it proves to be compatible with existing cars. Some manufacturers offer 'flexi-fuel' cars that can run on bioethanol blends up to E85 - a mix of 85 per cent bioethanol with 15 per cent petrol, as well as unblended petrol.

Some manufacturers also allow the use of higher blends of biodiesel in their cars (check with your car manufacturer). It is important that only high quality biodiesel meeting the EU quality standard - EN 14214 is used.

There are currently a limited number of fuel stations that offer this fuel, but the number is set to grow in the future. To find out where your nearest fuel station is, follow the link below.

• Transport advice - refuelling stations Opens new window

More Useful Links

• Greener fuels for cars