Glossary

Glossary of terms used for renewable and low carbon road fuels

The two tables below were produced by RTFA, SMMT, UKPIA and Zemo Partnership with the aim of improving understanding of terms used for renewable and low carbon road transport fuels.  

This first draft is being sent to members of the above organisations for comment.  If you disagree with a definition or feel it could be improved, or if you spot any omissions please click here to contact Gaynor Hartnell.

Liquid fuels  (scroll down for gaseous fuels)

Term (and acronym)Meaning
1G (First generation)Term describing biofuel feedstocks that come directly from an energy crop
2G (Second generation)Term describing biofuel feedstocks that come from waste plant material
B100Pure biodiesel/FAME, typically meeting the requirements of BS EN 14214
B20A blend of up to 20% biodiesel / FAME (meeting BS EN 14214) with the remainder petroleum diesel (meeting BS EN 590) which when combined typically meet BS EN 16709
B30A blend of up to 30% biodiesel / FAME (meeting BS EN 14214) with the remainder petroleum diesel (meeting BS EN 590) which when combined typically meet BS EN 16709
B7A blend of up to 7% biodiesel / FAME with the remainder petroleum diesel. This is the diesel fuel sold at retail outlets (filling stations used by the public to fill their diesel cars) and typically meets BS EN 590
Bio petrol / biogasolineA hydrocarbon made entirely from renewable sources which is functionally equivalent to petrol
BioblendNo longer a commonly used term, but defined in the Hydrocarbon Oil Duties Act as "Any mixture that is produced by mixing both: biodiesel and heavy oil that has not been charged with the excise duty on hydrocarbon oil"
BiobutaneButane (C₄H₁₀) derived from renewable sources
BiodieselA renewable liquid fuel consisting predominantly of Fatty Acid Methyl Ester (FAME) and meeting the requirements of BS EN 14214
BioethanolEthanol made from the fermentation of biomass and meeting the requirements of EN 15376
Bioethanol blendA blend of bioethanol and petroleum oil
BiomethanolA renewable liquid fuel consisting predominantly of methanol (CH3OH) which may be blended into gasoline
Blend wallThe maximum percentage of a particular renewable fuel that can be blended into retail fuels while meeting conventional fuel standards
Development fuelA fuel meeting the RTFO eligibility criteria for the development fuels sub target, i.e. A fuel made from a waste or a RFNBO, but not made from segregated oils or fats

And which is one of the following fuel types:
·         Hydrogen, biosynthetic natural gas (BioSNG),
·         Sustainable Aviation Fuel or
·         a fuel able to be blended at levels over 25% by volume and still meet the EN 228 or EN590 fuel specifications
DME (Dimethyl ether)Dimethyl ether (C2H6O), can be liquified under low pressure and used as an alternative to diesel. Can be synthesised from renewables (see rDME)
Drop-in fuelDrop in fuels are alternatives to fossil fuels that can be blended at higher than average levels into standard fuels without requiring changes to vehicles or infrastructure. (Some fuels commonly described as “drop in” may not meet current technical fuel standards (EN590 / 228) in all respects, but are warranted by OEMs to be used in certain vehicles at any blend level (up to 100%)
E10A blend of up to 10% bioethanol (meeting BS EN 15376) with the remainder petroleum petrol which when combined typically meet BS EN 228
E5A blend of up to 5% bioethanol (meeting BS EN 15376) with the remainder petroleum petrol which when combined typically meet BS EN 228.
e-fuelA specific subset of synthetic fuels that use hydrogen from renewable sources
ETBE (Ethyl tertiary butyl ether)A flammable liquid used as an additive in petrol. It is produced by reacting isobutene with ethanol and can be made using renewable sources. (Chemical formula C6H14O)
ETG or E2G (Ethanol-to-Gasoline)The process that converts ethanol (or bioethanol) to gasoline via dehydration and oligomerization usually over a zeolite catalyst.
FAME (Fatty Acid Methyl Esters)Pure biodiesel, typically meeting the requirements of BS EN 14214
FT (Fischer Tropsch reaction)A collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen (or "syngas") into liquid hydrocarbons
GtL (Gas-to-liquid)These are all synthetic fuels, made from methane or syngas (from gasification) converted to a liquid hydrocarbon through the FT process.

• Renewable sources include:
o Syngas (from the gasification of pure biomass)
o Biogas
o BioSNG (i.e. derived from syngas from the gasification of pure biomass)
o RFNBO methane, i.e. methane made from reacting renewable Hydrogen with CO2 (in which case it could be referred to as an e-fuel)

• Fossil fuel sources include:
o natural gas / gasified coal
o Recycled carbon fuel

Or it could be a combination of the above. E.g. syngas from gasification of a mixed waste containing biogenic and recycled carbon feedstock (in which case the resulting fuel would be a part renewable and part RCF fuel)

HBBF (High blend biofuel)A term often used for fuels with a renewable content that is greater than that of the retail equivalent. E.g. B20, B30 and B100 are all fuels with high blend of biodiesel compared to B7, plus E15, E20 and above (in countries where E10 is the retail grade). (Biomethane could also be supplied in a blend with natural gas (at any proportion))
HVO (Hydrotreated Vegetable Oil)A paraffinic diesel very similar to petroleum diesel but made by the hydrotreatment of vegetable oils or other lipids, typically meeting the requirements of BS EN 15940
LCF (Low Carbon Fuel)Fuels that can provide GHG savings compared to fossil fuels on a life-cycle basis
LPGGases derived from petroleum sources in liquid form; can be any mixture of propane and butane
MTBE (Methyl tertiary butyl ether)A flammable liquid used as an additive in petrol. It is produced by reacting isobutene with methanol and can be made using renewable sources. Chemical formula C5H12O
MTG or M2G (Methanol-to-Gasoline)The process that converts methanol (or biomethanol) to gasoline. Methanol is first converted to dimethyl ether by being passed over a gamma-alumina catalyst. The methyl ether is then passed over a zeolite catalyst to oligomerize into longer chain hydrocarbons to gasoline.
Off road biodieselA blend of up to biodiesel / FAME and petroleum diesel used for off-road applications, such as in agriculture, rail or construction. Typically this will meet the requirements of BS EN 590 or BS 2869
Paraffinic dieselA fuel comprising predominantly alkanes that is functionally equivalent to diesel. It can be made by hydrotreating lipids or via the gas to liquid or power to liquid routes. It typically meets the requirements of BS EN 15940
PetroleumPetroleum is a naturally occurring liquid found beneath the earth's surface that can be refined into fuel. Petroleum is a fossil fuel, meaning that it has been created by the decomposition of organic matter over millions of years
PtL (Power-to-Liquid)See the definition of synthetic fuel
Pure bio oilA fuel type classification used by RTFO Unit which includes fuels referred to as "Pure vegetable oil" in previous years' RTFO statistical reports
RCF (Recycled Carbon Fuel)Recycled carbon fuels (RCFs) are fuels produced from fossil wastes that cannot be avoided, reused or recycled and have the potential to reduce GHG emissions relative to conventional transport fuels. Feedstocks include industrial waste gases and the fossil-derived fraction of municipal solid waste (e.g. non-recyclable plastic). Some feedstocks can be considered part renewable and part RCF when combined with biogenic material such as food waste"
rDME (Dimethyl ether)DME synthesised from renewable feedstocks. For the potential renewable sources, see definition of GtL. Chemical formula C2H6O
Renewable dieselA common term for various forms of non-fossil derived diesel fuel, including FAME, HVO or paraffinic diesel (when made from renewable sources)
RFNBO (Renewable Fuel of Non-Biological Origin)Rather than from biomass, the energy content of a RFNBO typically comes from renewable electricity
RME (Rapeseed oil Methyl Ester)Biodiesel produced from rapeseed oil
Synthetic FuelA fuel which is produced from a mix of hydrogen and a carbon source (e.g. carbon monoxide or carbon dioxide). A synthetic fuel can also be classed as a renewable fuel if the hydrogen is produced from a renewable source and any carbon source used is from a renewable or unavoidable carbon stream, for example an industrial process where carbon dioxide would otherwise be vented into the atmosphere, in which case it would be a RFNBO
TME (Tallow Methyl Ester)Biodiesel produced from tallow
UCOMEBiodiesel produced from used cooking oil

Gaseous fuels (see above for liquid fuels)

Term (and acronym)Meaning
BioCNGA term used for compressed biomethane. This can also be referred to as CBM – compressed biomethane (not to be confused with Coal Bed Methane).
BioLNGA term used for liquefied biomethane. This can also be referred to as LBM – liquified biomethane.
BioLPGAnother term for either biopropane or biobutane
BiomethaneMethane (CH4) derived from biomass, either via a biological route – anaerobic digestion – (in a dedicated AD plant, sewage treatment works or landfill) or via a thermal route via gasification and methanation of the syngas
BiopropanePropane (C3H8) made from biomass. Most commonly derived as a by-product of the HVO production process
BiobutaneButane (C4H10) made from biomass. Most commonly derived as a by-product of the HVO production process
BioSNG (bio Substitute Natural Gas)Term used for renewable methane via the thermal route, (unspecified as to whether it is compressed or liquified). (This qualifies as a development fuel (if made from waste) under the RTFO)
CBM (Compressed Biomethane)Compressed Biomethane. (NB not to be confused with Coal Bed Methane)
LBM (Liquified Biomethane)Biomethane (in liquified form). Liquified Bio Methane.
RFNBO (Renewable Fuel of Non-Biological Origin)Rather than from biomass, the energy content of a RFNBO typically comes from renewable electricity
SNG (Synthetic / Substitute Natural Gas)Gas (mainly methane) which can be produced by a number of routes (which may be more commonly referred to by more specific terminology. E.g. if produced by anaerobic digestion and CO2 removal = biomethane; gasification and gas clean up of biomass = bioSNG. It can also be produced by the gasification of coal