An excise is a tax on alcohol, tobacco, fuel and petroleum products produced or manufactured in Australia. Fuel blending (combining fuel with another substance or substances, whether fuel or otherwise), including with ethanol and biodiesel, is considered manufacturing and is therefore subject to the excise tariffs laid out below. There are some exceptions, including to blends subject to a legislative determination, and blends unable to be used in an internal combustion engine, when duties applicable to the components of the blend have been paid. The following chart, provided by the ATO, will help you to determine if your product is subject to excise:

excise framework

Further information on the excise treatment of fuel blends is available here.

[Last Updated 31 August 2015] Note: Excise rates are indexed on the 1 February and 1 August each year.

The various types of fuel available in Australia are subject to different excise rates.  A summary of current excise rates as displayed on the ATO website, is provided below.
Imported fuels and petroleum products are also subject to a customs duty equivalent to the excise.  Imported Biodiesel and Ethanol pay the equivalent excise to Diesel and Petrol respectively.  locally produced product is currently excise free.

Sub item Unit Description of Goods Rate
10.21 L Biodiesel The rate of duty worked out under section 6J
10.20 L Denatured ethanol for use as fuel in an internal combustion engine The rate of duty worked out under section 6H
10.1 L Petrol $0.392 per litre
10.10 L Diesel $0.392 per litre
10.7 L Blends of gasoline and ethanol The amount of duty worked out under section 6G (using $0.392 per litre at step 3 at 6G)
10.12 L Blends of diesel and either biodiesel or ethanol, or both The amount of duty worked out under section 6G (using $0.392 per litre at step 3 at 6G)
10.19A L LPG $0.128 per litre
10.19B kg LNG $0.268 per kilogram
10.19C kg CNG $0.268 per kilogram
10.15 L Heating oil $0.392 per litre
10.6 L Gasoline for use as fuel in aircraft $0.03556 per litre
10.16 L Kerosene (other than for use as fuel in aircraft) $0.389 per litre
10.17 L Kerosene for use as fuel in aircraft $0.03556 per litre
10.18 L Fuel oil $0.392 per litre

The manufacturing of biofuel, as well as blending it with other excisable goods, is subject to licenses in Australia. The type of license required, i.e. manufacturing or storage, depends upon the activity undertaken by the business. For those looking to produce or blend biofuels, more information on the required license and excises payable is available from the ATO.