Transport biofuels provide not only a renewable and sustainable alternative to the finite resource of the oil used in the vast majority of cars, but are also biodegradable, non-toxic and can provide significant carbon savings compared to fossil fuel. A particular advantage of biofuels is that they can be used in all vehicles from buses to boats, and require little or no engine modification. Their use can lead to a cut in carbon dioxide emissions of 50 – 80% compared with fossil fuels.

Renewable transport fuels fall into these categories:

Biodiesel

Biodiesel is produced through a process known as transesterification, which separates glycerine from vegetable oil, leaving biodiesel as a product. The glycerine can then be used in the making of other products, such as soap. Biodiesel can be used as a straight fuel, or blended with mineral diesel to create a diesel blend. Both types can be used without any engine modification.

Bioethanol

Bioethanol is produced from plants such as maize, wheat, sugar beet and sugar cane, through a process of fermentation, distillation and dehydration. It can be used as a 5% blend with petrol in unmodified engines. Blends range from E5, E10, E15 to E85.

Advanced Biofuels

Many advanced biofuels, both bioethanol and biodiesel, are under development such as lignocellulosic ethanol, fuel from algae, biohydrogen, biomethanol, DMF, BioDME, Fischer-Tropsch diesel, biohydrogen diesel, mixed alcohols and wood diesel. The state of development and commercialisation of these advanced biofuels varies but all currently require policy support.

Hydrotreated Vegetable Oil (HVO)

HVO is a renewable diesel biofuel made by hydrogenating vegetable oils or waste animal fats. HVO has a paraffinic structure very similar to fossil diesel, giving it excellent combustion properties, long shelf life, and compatibility with modern diesel engines without modifications. It produces significantly lower greenhouse gas emissions and particulates, making it a cleaner, sustainable substitute for conventional diesel.

Recycled Carbon Fuels (RCFs)

RCFs are made from recycled carbon sources, such as waste gas captured from industrial processes or through the liquefaction of fossil waste material. While not derived from renewable resources, RCFs still provide benefit in reducing emissions by recycling carbon that would otherwise be emitted into the atmosphere.

Recycled Carbon Fuels (RCFs) can be produced from sources such as End-of-Life Tyres (ELTs), where the process of pyrolysis or gasification to produce pyrolysis oil can be refined into diesel or jet fuel.

Renewable Fuels of Non-Biological Origin (RFNBO)  

Power-to-liquid (PtL) fuels are synthetic fuels produced by using renewable electricity to generate hydrogen via water electrolysis, which is then combined with captured CO2 to create liquid hydrocarbons such as e-diesel, e-kerosene, or e-methanol. These fuels can directly replace conventional fossil-based fuels in existing engines, ships, and aircraft, enabling low-carbon transport without requiring major infrastructure changes.

Ammonia is a chemical made up of hydrogen and nitrogen, which eliminates direct CO2 emissions, is energy-dense, easy to transport, and can be made generated using renewable sources like wind or solar. This can be burned in combustion engines but may require blending with other fuels or modifying engines to handle ammonia characteristics.

Biomethane

Biomethane is the purification of biogas through the removal of any residual carbon dioxide to create pure biomethane. This naturally produced biomethane can then be injected into the gas grid.

 Biomethane can be upgraded from biogas and used as a renewable alternative to fossil natural gas in vehicles, either as compressed biomethane (CNG) or liquefied biomethane (LNG). It can fuel vans, buses, HGVs and ships with adapted engines or gas-compatible systems, significantly reducing greenhouse gas emissions in transport. 4

Hydrogen

Hydrogen can be produced from renewable energy sources, such as wind and solar through water electrolysis. When used in fuel cells, hydrogen generates electricity to power vehicles, emitting only water vapour as a byproduct. Challenges remain in scaling up production, building refuelling infrastructure, and reducing costs to make hydrogen-based transport widely accessible.

For more detailed information please see the REA’s Renewable Transport Fuels Forum.