What is ethanol?
- Ethanol is a type of alcohol produced through the fermentation of vegetable matter.
- Grain and sugarcane are commonly utilised but the use of less valuable or waste feedstocks such as grasses etc. may become commercially viable in the future.
- With modification, vehicles can operate on 100 percent ethanol, but it is usually blended with petrol at concentrations of around 10 to 15 percent.
In Australia, ethanol content is generally limited to 10 percent (E10), although blends containing 85 percent ethanol (E85) are available from a small number of outlets.
The Australian Fuel Quality Standards define the environmental and operability standards for all fuels, including ethanol blends. It limits ethanol content of petrol to 10 percent (E10). E85 falls outside the Fuel Quality Standards but is a permitted product.
- Most, but not all, petrol vehicles sold in Australia after 1986 can use E10.
- Some manufacturers produce vehicles that will operate on higher and varying concentrations of ethanol, such as E85. However, this fuel has not been widely accepted due to the significant increase in fuel consumption it produces.
- Ethanol blends are not recommended for pre-1986 vehicles or those fitted with a carburettor.
- Ethanol blends are not recommended for boats due to issues with phase separation (see Potential ethanol problems for an explanation)
- Ethanol is also not suitable for aircraft and may not be suitable for some motorcycles and small engines (mowers etc.). The equipment manufacturer’s advice should be sought before using ethanol blends.
As ethanol has a slightly lower energy content than petrol, its use will increase fuel consumption. Compared to unleaded petrol, an E10 blend will increase fuel usage by approximately three percent.
E10 therefore must be three percent cheaper than ULP to offset the increased consumption.
Potential ethanol problems
- Problems that could arise in incompatible vehicles are: fuel system damage due to material incompatibility, and drivability problems such as stalling, vapour locking, flat spotting etc.
- Ethanol has a scouring effect on fuel systems and its use in poorly maintained vehicles may result in filter blockages. Once clean, the system should remain clean with continued use of ethanol-blended fuel.
- Ethanol will absorb small amounts of water, however water content above about 0.5 percent will cause the ethanol, and the water mixed with it, to drop out of suspension and fall to the bottom of the tank. This is called Phase Separation. This will cause poor running, or more likely a no-start situation.
Ethanol is a clean burning fuel that produces less greenhouse gases than unleaded petrol. However, when the growing of crops and the production and use of ethanol is compared with the production and use of petrol, the environmental gains may be small, and dependent on the crops and the production methods used.
Determining if your car accepts ethanol
Later model E10 compatible vehicles will have a label in the fuel filler indicating suitability. It will usually also be shown in the car’s handbook.
Alternatively, this list will be helpful for post 2000 cars:-
for a more comprehensive list.
If compatibility can’t be confirmed, we recommend that you don’t use ethanol blends. At this stage we expect that most service stations will continue to offer normal ULP, however if this isn’t the case in your area you may have to find an alternative outlet. Alternatively, you may wish to consider one of the higher cost non-ethanol premium fuels that are commonly available.
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