Answers to common questions about low carbon liquid fuels: what they are, what goes into making them, how they are used in Australia, and how emissions claims are verified. Every answer links to the evidence behind it. Search for a word or phrase, filter by category, or browse the key terms at the end of the page.
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The basics
Using low carbon liquid fuels
Feedstocks and production
Emissions and sustainability
Role alongside other technologies
Australia, industry and policy
Key terms
B
Bagasse: The fibrous material left after sugarcane is crushed to extract juice. It is currently used to produce renewable electricity as a source of baseload power for the mill and electricity network, but can also be converted into low carbon fuels.
Biodiesel: A diesel-like fuel made from oils and fats through a process of transesterification into Fatty Acid Methyl Esters (FAME). It is chemically different from petroleum diesel and is used in blends up to a set limit.
Biofuel: A fuel made from biological materials such as crops, animal fats, wastes or residues. Biofuels make up most, but not all, of the low carbon liquid fuel category.
Blend limit: The maximum proportion of a low carbon fuel that may be mixed with a conventional fuel. Blends are named for the low carbon share, so E10 is petrol containing up to 10% ethanol.
C
Carbon intensity: The greenhouse gas emissions associated with a fuel, expressed per unit of energy it delivers. It allows different fuels to be compared on a consistent basis.
Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA): A scheme run by the International Civil Aviation Organization. It sets sustainability criteria and life-cycle emissions methods for eligible aviation fuels.
Certification: Independent assessment confirming that a fuel meets a published set of rules. The resulting certificate turns a claim into evidence that regulators and buyers can rely on.
Chain of custody: The method used to track a batch of fuel through the supply chain so that the fuel delivered can be matched to the claim made about it.
Co-processing: Running renewable feedstocks through an existing refinery alongside crude oil, producing fuel that contains a renewable share without building a dedicated plant.
D
Drop-in fuel: A fuel that meets the same specification as the fuel it replaces, so it can be used in existing engines, storage and distribution without modification.
E
E-fuel: A liquid fuel made from renewable electricity and captured carbon dioxide rather than from plant or waste material. Also called an electrofuel or power-to-liquid fuel.
E10: Petrol containing up to 10% ethanol, sold at service stations across much of Australia.
Electrolysis: Using electricity to split water into hydrogen and oxygen. When the electricity is renewable, the hydrogen produced can be used as a low emissions fuel or as an input to e-fuels.
Ethanol: An alcohol fuel produced by fermenting sugars or starches such as sugarcane, molasses, wheat or sorghum. In Australia it is mainly blended into petrol.
F
Feedstock: The raw material a fuel is made from, such as canola oil, sugarcane, straw, tallow or used cooking oil.
Fuel cell: A device that generates electricity by reacting hydrogen with oxygen from the air, producing water as the only by-product at the point of use. Unlike a battery, which stores electricity, a fuel cell generates it while the vehicle runs.
G
Guarantee of Origin: An Australian Government scheme, administered by the Clean Energy Regulator, that records the emissions associated with producing certain commodities, including low carbon liquid fuels.
H
Hard to abate: Sectors where emissions are difficult to reduce with current technology, usually because electrification is impractical. Aviation, shipping and heavy freight are common examples.
Hydrogen: A gaseous energy carrier. It can be produced by using renewable electricity to split water, and used in a fuel cell, burned in an engine, or combined with captured carbon dioxide to make e-fuels. Hydrogen is a gas rather than a liquid fuel, so it is a separate option alongside low carbon liquid fuels.
Hydroprocessed Esters and Fatty Acids (HEFA): The most widely used production pathway today for renewable diesel and sustainable aviation fuel, using oils and fats as feedstock.
I
Indirect land use change: The displacement of food or feed production when land is switched to growing fuel feedstock, which may cause land to be cleared elsewhere. It is estimated through modelling and is a contested area of emissions accounting.
L
Life-cycle emissions: The greenhouse gas emissions produced across every stage of a fuel’s existence: growing or collecting the feedstock, converting it into fuel, distributing it, and burning it.
M
Mass balance: A chain-of-custody model in which certified and uncertified material may be physically mixed, provided the certified volume entering the system matches the volume claimed leaving it.
R
Renewable diesel: A diesel-equivalent fuel made from oils and fats and processed to meet the diesel specification, so it can be used in existing diesel engines and infrastructure. Also called hydrotreated vegetable oil (HVO).
S
Sustainable aviation fuel (SAF): Aviation fuel made from feedstocks such as wastes, residues and oils, or from renewable electricity and captured carbon dioxide. It is currently used as a blend with conventional jet fuel.
T
Tallow: Rendered animal fat, a by-product of meat processing, used as a feedstock for renewable diesel and sustainable aviation fuel.
Technology readiness level (TRL): A nine-point scale for how developed a technology is, from laboratory research and concept testing (TRL 1–3), through pilot-scale demonstration (TRL 4–6), to technologies proven in full-scale commercial operation (TRL 7–9).
U
Used cooking oil (UCO): Cooking oil collected from food businesses after use, and a major feedstock for renewable diesel and sustainable aviation fuel.
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