In 2008, the Federal Parliament approved legislation capping the use of ethanol in petrol to 10% (E10) and requiring that petrol stations adequately inform consumers if they are using petrol that includes ethanol.
What is Ethanol?
Ethanol (ethyl alcohol) is a clear, colourless liquid, generally manufactured from grain or sugar. (Currently around 90% of Australia’s ethanol is produced from wheat). Blending ethanol and petrol in various proportions has been put forward as a means of reducing greenhouse gas emissions and alleviating adverse economic conditions in the sugar industry.
Ethanol can be considered as a renewable fuel when produced from sustainable agricultural sources and has potential for cutting greenhouse gas emissions. Whether this potential is realised depends on the feedstock and the technology used in the production process as well as the distribution and blending procedures.
When determining the overall environmental impacts or benefits of ethanol use, the ‘whole of life’ effects must be measured, including the impacts of the production of wheat or sugar produced solely for ethanol production.
Ethanol is more costly to produce than petrol and requires its own storage and distribution infrastructure.
Ethanol can be used as an automotive fuel by itself and can be mixed with petrol to form an ethanol/petrol blend. Pure ethanol can only be used in specially designed engines.
Vehicle fuel economy is reduced when petrol is diluted with ethanol because of its lower energy content.
Is using Ethanol blended fuel better for the environment than fuel without ethanol?
Results of studies conducted around the world on emissions outcomes and performance of ethanol blends are often contradictory. Emissions from ethanol blended fuels vary markedly between different ethanol blends and different vehicle technologies.
Within the Australian context, the use of ethanol blends of 10% (E10) has been found to result in:
- Decreased emissions of carbon monoxide (CO) (32%) and hydrocarbons (HC) (12%);
- Increases in non-regulated toxics: acetaldehyde (180%) and formaldehyde (25%);
- A slight (1%) increase in nitrogen oxides; and
- Decreases in non-regulated toxics: 1-3 butadiene (19%), benzene (27%).
Recent Australian life-cycle analysis work has revealed that E10 blends are considered greenhouse neutral.
Will I consume less fuel by using Ethanol blended fuel compared with petrol?
Ethanol has a lower energy content than petrol, the 1998 Australian field trial by Apace Research observed a fuel consumption increase of up to 2.8% with E10. Because of this higher fuel consumption there are fewer kilometres per tank of fuel, so ethanol blended fuels will cost motorists more.
Will Ethanol damage my vehicle or affect its performance?
Most metal components in fuel systems will corrode or rust in the presence of water. Ethanol increases petrol's ability to absorb water without separating and Ethanol blended petrol can therefore ‘hold’ more water and carry this through the engine. The greater the concentration of ethanol the greater the ability to ‘hold’ water.
Several studies have examined the effect of E10 on fuel tanks and fuel system components and have concluded that ethanol up to 10% does not increase corrosion in normal, everyday operation.
Ethanol blends may have a deteriorating effect on the rubber components of an engine. Other additives, such as benzene may also have an effect.
In older models, deposits in fuel tanks and fuel lines are occasionally loosened by E10, and the fuel filter may become plugged. This is remedied by a fuel filter change. If very Ethanol rich fuel is used this may cause an engine to stall.
Laboratory tests have shown that blends of 20% pure Ethanol in petrol can damage some conventional automotive paint.
A number of motor vehicle and marine engine manufacturers advise their warranties would be voided where fuel blends of greater than 10% ethanol have been used.
A list of vehicles that manufacturers have allowed the use of ethanol blended fuel, as compiled by the Federal Chamber of Automotive Industries.